Edgar's not on top of their statements

Edgar's have messed up my account. I get messages stating that I owe them money. They said they have no evidence of payments made for the last 6 months. I had to resend proof of payment for each month. I am still getting messages to pay them an outstanding balance and now my card won't work to make a payment. I am concerned that their error is going to result in a negative credit rating for me. Not happy. Been a Customer for 20 years.