Should I cancel my visa check card?

I received a call telling me that I did not pay a payday loan form sept 2012. They said I owed them over 800.00 dollars to pay off. I thought this was odd because I did have a loan in Sept; I forgot about it during the next pay, but I called the company worked with them and they took it out of my next check with a processing fee . So since they had the date, the lady said it was for fees I did not pay off, So I made a payment arangment with her, I did not sign anything. I gave her my card information and paid 50 dollars, I set up 6 more payments of 125 each. I did this because she said s summons was on the way and they would go to my work. After I hung up, I got another call from a diffrent company saying the same thing wanting payment. I pulled up on line and saw that there are scams like this going on. Should I cancel my credit card so they can not take out more money? what happens if there truly is a mix up and it is not showing I paid it?