Collection agency dollar amounts and dates not adding up

I have been dealing with a collection agency since January 2017 trying to resolve my debt with them. I have been paying them every 2 weeks up until recently when I realized that the dates and the amounts that we had agreed upon are not adding up. According to my Credit Karma report not one amount or date that we agreed to have matched. I now feel that I am being played by the credit agency and want to dispute this. Do I have grounds for this or will it reset my SOL?(I was not aware of the SOL until recently and have paid some old accounts off according to CK)