I was sent a letter to owe the amount of {$51.00} on my XXXX XXXX credit card account. I paid off all amount that was due on that credit card and it currently shows on my online account that I have no amount due at this time. 
The last payment I paid in full was in XXXX XXXX, 2015. 
I do not understand why I am receiving a letter from the collection department for an amount that I did not even spend. Please fix this false statement.