can I use SOL as a defense if it went past from the original creditor prior to Arizona changing it's SOL from 3 years to 6 years? Or is it that when that changed it retros back?
The SOL defense is not simple. There are many different SOLs -- ranging from 1 - 6 years -- for different claims. Typically, SOL for claims arising out of written obligations is 6 years. It has been that way for a long time. Of course, there are exceptions. You should consult with an attorney that handles debt collection defense cases to evaluate your options. I recommend Richard Groves, http://azconsumerlaw.com/.
Mr. Choi is correct. Nothing short of a consultation with a consumer-rights attorney, and immediately, will meet your needs. Consumers seem to universally assume that the statute of limitations is one exact and absolute number. It is much more complicated than that, and an inquiry into the facts of the debt and your payments is needed. As well, the court pleadings to effectively raise an available SOL defense are not safely a DIY enterprise.
Best wishes for a favorable outcome, and please remember to designate a best answer.