Employer is lying and shorted my last check 200.00

On 10-17-2006 I started a job at Hauser Pharmaceuticals as a customer service Rep. I was told NOT to quote pricing until I had been trained. I started asking questions, like why are we shipping to a residential address with no state license on file? I was told when a doctor retires he can order meds until he dies. OK! Then I seen a young boy playing in the warehouse where many medications are stored, I asked, Is he soppose to be back there? I was told, "Its ok, he is the owners grandson". Hmm...OK! Then I asked my trainer for some tylenol for a headache and she responded,"there is something in the kitchen drawer". I went back there and found an open bottle of prescription medication, I explained, Its ok, I will go on lunch and grab something. On 11-9 I was called into the Supervisor (Terry) office, and the office manager (Kathy), and Terry was in there. Terry said, " we have decided to end this Business relationship" I asked, Why? She first said, "we do not need a reaso". I asked for one anyway, then she said I was quoting prices and then lying about it. I said, NO, I never quoted prices, I have never been trained too! (there would be NO motive). They then said, Sign here and we will mail your last paycheck. I was in SHOCK, I signed, then at the top of the paper, I noticed it said,"resignation". I said, Hey, wait, I did NOT resign, you fired me! Terry said, "its standard procedure". They then walked me out. Confused and scared, I went home. On 11-11, I filed for UC online. Explaining the situation to them. On 11-17 I received a certified letter from hauser that said " We accept your resignation effective November 9,2006". Also enclosed was a final paycheck. It read 54.50 hours (correct)..10.00 an hour..(correct and the gross pay 365.00 (INCORRECT). They will NOt answer my calls. These people have turned my life upside down! I have NEVER been fired until now. What am I soppose to do? I am looking for a job but cannot understand what they are trying to do to me and WHY?