Collection agency stopped collecting!

[SAMAGEE]

Last year I made a verbal agreement with a collection agency that took over a written off Visa account. Last month they returned my check & said to begin making payments to the company that had written off the Visa. This account shows up twice on my credit report -the written off Visa balance & the exaggerated amount dreamed up by the collection agency. If I pay Visa, which amount am I suppose to pay & where will the money be applied that I have paid so far? The balance according to the collection agency is not what I owe Visa! If I pay Visa, what about the collection agency's account on my credit report?
Also, please advise me what the SOL is for Arizona for a credit card debt.
I live in Mississippi, the debts mentioned above were incurred in Texas.
Thank you.