Sprinkler Smart will not correct their poor workmanship. Valencia California

Sprinkler Smart came out 8/19/09 to fix sprinkler zone #1 not coming on with automatic timer, we had no other issues such as leakage. The repair guy asked us if we were interested in buying a key & lock for our sprinkler box. We had left it unlocked for him since we were expecting him. Then he asked if were interested in adding a pressure regulator to distribute the water evenly throughout the yard but not a necessity, the cost is approx $300-$400. We made a quick call and contacted a professional for a second opinion and they stated that we did not need a pressure regulator to fix our timer issue.  So we said no, and he said that was okay, if we decided to in the future let them know, he replaced the valve to fix timer issue . The valve that he replaced is now leaking, we called on 9/5/09 to report the issue, we called again on 9/8/09 and spoke to Steve and addressed our issue, he was very rude and stated that they knew it was going to leak and they will not come out unless we pay for a new service charge visit and commit to adding a pressure regulator to our system.  I asked him if they knew the valve was going to leak why are they refusing to fix it now without a pressure regulator and did not refuse at the time they replaced the valve?  Again our initial issue was a timer problem, we have not had a leaking problem until Sprinkler Smart came out. The sprinkler system has 6 zones, the only one that leaks is the valve they replaced in zone #1. They refuse to address the issue as a work guarantee issue.  The worst part about this is that the valve did not need to be replaced, all that needed to be replaced was the solenoid located on top of the valve.  In the short amount of time that we dealt with Sprinkler Smart they seem to be a company that wants to fix things that don't need to fixed so they can get as much money as they can from the customer.  As I mentioned before the repair guy wanted to sell us a lock & key for the sprinkler box that we intentionally left unlocked for him and he insisted that we replace it after I told him we have a key and just unlocked for him before the got here.  Then he wanted to sell us the pressure regulator which had nothing to do with our timer issue.  We are suspicious that they may have rigged the valve so that it would leak so that we would call them back because they said on the phone that they knew it was going to leak if we did not put in the pressure regulator, the repair guy that came out just said it was a good idea not that we had to have it to avoid any leaks, and we did not have a problem with leakage before they came out.   Now Steve, person that answered the call at the office, very rude, loud and insulting, insists that we order and pay for the pressure regulator and pay for a new service charge or they will not come out.  It has been only approx. 18 days from their first visit to the day we have reported the problem.   So in other words, they are not going to guarantee their work.