Rude Customer Service

I called today to check on my Extended Service plan payment. I purchased in January, called back soon after to pay in full. received bill today stating I owed more on the account. I called and explained that I spoke with customer service soon after opening the account to pay the invoice in full to avoid extra charges. Only to have the Rep ramble on about service charges and billing amounts for longer than needed. I requested to speak with a supervisor she put me on hold and then got back on the line and told me a different name and said she was a supervisor. Debbie commenced to telling me how it was my fault and my account didn't show that I requested to pay in full, all this without ever asking me how she could help me or what my issues were. When she finally stopped long enough for me to speak. I told he that the customer service received so far was poor at best you haven't listened to me or ask how we can resolve this issue. I just wanted to verify my payoff and try to avoid the fees, this has made me second guess my decision to purchase from Good Sam. how hard of a time will I get making a claim, if i get this much hassle trying to make a payment.