I am an Ex- geek squad employee. I've seen cases similar to this happen a lot. basically once the service center says "liquid damage" somebody has to pay them to fix it. (they don't care who, you, the local store. corporate office UPS /Fedex the tooth fairy etc. )
the solution here is really simple. if the store already admitted the liquid damage did not exist when you dropped it off. call the store and ask what time tyler will be working. (try to figure out what day he is off.) then hang up. call again and ask for Josh. if you get him. ask him what time he gets off. or when he is working again etc. find a time when Josh is around and tyler isn't
come into the store. send it in again with the magic words in the tag. "store confirmed liquid damage didn't exist when customer dropped off. store preapproves cost of repair" in the tag. you sign it. the the geek agent signs it. then request a photocopy of that paperwork with signatures. wording is critical.
Mike P is NOT your friend. the words "Customer is disputing that it was there when he brought it in. Please diagnose again, escalate to a team lead/manager" is completely useless and actually passive-agressive. (it's like saying customer believes in UFO's or alien beings) nobody cares what you personally believe or your feelings. just the facts.
the problem here is that Tyler has probably yelled at josh already or told him not to speak with you etc.
now if the service center happens to call you to approve the estimate you say yes. (otherwise your back to zero again) laptop is now fixed back at the store. now when you go to pick it up either a) the store was billed and you owe nothing. b) they ask you for $$$ you can refuse showing the signed paperwork stating the store is covering the cost.
if they still wont give it to you. politely excuse yourself & say you need to call your wife. pickup the phone and call the police about a laptop being stolen at the store. when the officer arrives basically state that it's your laptop & you want it back and the store is refusing to give you your property and you want to file a criminal complaint. basically your position is it's your laptop your taking it with you. most of the time the police will allow you to take your property home with you. and if best buy wants paid. they would have to sue you (civil issue) which they won't do.
if some reason the police say you must pay or the store can keep the item. (or if the officer is a jerk and says if you leave with your own property without paying the service fee he will arrest you) pay on your credit card. give a swiggle line for a signature. then call the credit card company to file a dispute.
if Tyler says the liquid damage was "pre-existing" then the argument (which best buy loves to make) is that the service contract is a legal document. and both you & an authorized representative from best buy signed.
The original document stating the condition of the unit which I assume didn't mention stains around the mouse pad etc (this is why the 2nd time mike checked it in. he noted carefully the condition to CYA. (this is why some geek agents are crafty to say things like "no visable damage I could see on unit" in the condition field. you also need to be careful, because you sign when picking up the unit. it doesn't say I'm picking up the unit. it says "I recognize that repairs have been performed in a matter that is satisfactory to me. "
I cannot tell you how many times people came back to the store 2-3 days latter saying my desktop/laptop is dented or chipped it wasn't like that when I left it in only to have the store say the unit was in perfect condition when you picked it up. there's your signature. (the original form you signed on drop-off also states damage is to be reported on pickup)
Personally I suggest people cross this out and simply say write "picked up unit." and intial it.
if the geek agent refuses to create a tag with the language that the store will cover the costs. the last deal you can do. (believe it or not) ask if you have purchased the best buy service plan with accidental damage coverage. would it have covered this. when they say "yes" say I need to buy a new PC from best buy anyway. I do want to get that. can I get some credit for the old laptop. (in other words 50/50 blame) some managers will give you $200 store credit.. you spend $700 for a new unit + $300 for a service plan ($1000 total) 3days later return it for $1200 back.
when a best buy manager says "call corporate" and gives you the 1-800# that is actually outsourced to a 3rd party it's passing the buck. they will tell you that they are powerless and you need to contact the local store manager.
In the past others have had success in this group when I recommended calling the main corporate switchboard and asking for the "executive resolutions dept" (they handle hot issues from the media, TV news, press, or VIP people) they used to help people who posted on this website, but new reports indicate.. unless your a VIP or the media. they might tell you c'est la vie in which case you bring political pressure from your local TV News consumer help line. or file a lawsuit against best buy in your local small claims court.
Best of luck, keep us updated on your progress.