7th Avenue Accuse me of owing them money with Experian

Recently I received a letter from Experian advising me that 7th Avenue had submitted a report advising them they had charged off $113 that I had not paid.  I was so shocked because I had paid my account in full May, 2017. 

I have only had the 7th Avenue account a year or two and had planned to continue to use it when I moved to my own place since I looked at 7th Avenue as a potential supplier of furniture I might need. 

With this Experian letter, I immediately changed my mind.  I will now close the account.

Before I do that, however, I need to find out why they think I owe them money.  I'm waiting on a response to my letter.

I have always had a problem with the way 7th Avenue does business.  It's almost impossible to get to one's account online.  I don't know how many times, after I thought I had set up online access because I either couldn't access the account with the information I had used or the password wouldn't work or the email was incorrect.  At one point, I thought I had resolved all the issues only to find the next month I was wrong.  I'm competent with computers so I was stumped and annoyed.  I sent at least two letters, if not more, complaining about the situation to which I received no reply. 

Eventually, after more frustrataion, I finally was put with someone who was supposedly with the data processing area.  After my talk with him, I no longer had problems getting into the online account. 

Initially, I made payments on line.  They were properly credited.  When I retired, I started making payments via check.  They made it into my bank account and my statements showed they had been properly credited.  Then I started getting phone calls from someone who wanted me to call her from 8 a.m. to midnight or thereabouts. 

When I sent the last check, I was finished. 

Then I get the letter from Experian. That was the last straw.  I wouldn't do business with 7th Avenue now for anything.