In 1996, I obtained a credit card from Chase with a limit of $100. I thought the card had been paid off, so whenever I received correspondence from Chase, I discarded it because I assumed they were wanting me to increase my limit. I then started receiving calls from a collection agency that represented Chase for payment. To my surprise, the amount owed, I think by the time I started receiving calls, the balance was well over $1,000. The interest accelerated immediately due to late payment to a rate of 27%.

I did not respond to the collection agency, because I thought the account had been paid, but found that it had not. I contacted Chase directly and started paying. Then, due to loss of income, failed to keep up the pmts.

I received a letter today, from a "mediation" organization stating that they would like to serve as a neutral mediator in the suit filed against me by CACH, LLC as creditor. After investigating further, I determined through my credit report, that Chase apparently "transferred" the amount owed, which is now $2,600+. I have not received any kind of formal notification of suit, so I am unsure how CACH can file suit if they were not the original debtor.

If the original amount was charged off by Chase, how can CACH file suit if they just purchased an unpaid debt from Chase?

Check the statute of limitations in your state, it may have expired. If you pay anyone one red cent a new statute of limitations will open.