Parts geek sent 1 out of 5 parts, says all five shipped,seems like a scam/ con Internet

I ordered 5 running lights that go on top of my truck from partsgeek. I received a box, it was sealed, I opened it and saw only 1 part. There was bubble wrap, and no invoice, just one light, not the five that I had paid for ( funny how they had no problem receiving money for all FIVE)So I decide to contact partsgeek customer service.... Well the only option I found was a page in their site where I fill out an online form. I finish the form and thell them that I got my delivery but there were 4 parts missing. 

2 days later this is the response via email that iI received "Sorry for the delay on this matter, did you not receive your parts? I replied by clarifying that i did not receive all of my parts, this email from them seemed like a delay tactic. Why disnt they actually look into WHY only 1 light was in the box that said 5 lights where in it. Later that day I get another email saying that they contacted the shipper and that the package was delivered successfully and that I should check with my neighbors to see if they received the package. Why would they contact the shipping company when I stated that I received the package.

Rather the failure to put all parts into the box was intentional or just a miststill at this point the company is not being very helpful in correcting the situation. I fear that they are scamming and intentionally ripping people off. If I went into a store and paid for 1 item and took 5, I would be locked up. 

They have not even replied with possible reasons that the parts could be missing. I am wonder what their next response will be, will they just stop responding? Will they say I am lying and that all parts where in the box? Will they say someone at FedEx stole 4 parts and left one? If so why would they continue to use a company that steals from them? 

I have ordered from them before but it was only single items, not 5 items at once . Those orders came with no Issue . Why would this company treat a repeat customer like this?

I would have continued to buy many parts from them for years to come.  I wish I would have read the reports on them and had checked their bbb score which is a d-

Do  They have a policy of not sending all items with the sole purpose of making money, perhaps they didn't have all items in stock but wanted to make the money, and know they are in a situation where they cannot get in trouble, whatS the worst that can happen? I complaiN to better business bureau? Thats laughable, they don't care about that, their score is a D-. Am I going to go to me credit card company? Yes, but it seems like the credit card company's side with the big companies, from what I read, the cc companies will issue a credit and investigate, but then will side with the company and recharge you months later. 

Hopefully they just have poor customer service and poor record keeping etc etc and they will come through in the end and actually correct the situation but it is not looking good so far. Maybe at least If I make a fuss they will take care of the situation, butlow many people don't make a fuss? When I order online from a company I don't expect to have to fight for the items I paid for.