SNAP RTO, LLC and Midland Credit

Hi. I have a question about a collection letter I received from Midland Credit Management. There are a few things that concern me once I received their alleged validation of debt. I learned that the original creditor, SNAP RTO, LLC was not registered to do business in Texas but entered into contracts from 2019-2022, until it finally registered in April 2022. My contract along with many others in Texas were signed in 2019. I also noticed in my contract, it appointed me as the agent for SNAP RTO LLC, stating AQUISITION OF PROPERTY AS AGENT: " You are obtaining the Property as our AGENT. Which is odd because I did not know the deal to rent furniture came with fiduciary duties to be an agent for a company not registered to do business in Texas. Also, the contract charged 3x's the amount allowed in Texas, (Usuary) and Midland Credit Management is attempting to collect on this debt past the SOL even after I told them to stop contacting me and I have the emails to prove it. Also, I was told by an agent at Midland that even though the SOL passed to sue for the debt, I have a "legal" obligation to pay. I aminterested in suing them both because of the many resons aformentioned. Has anyone had a similar issue? I'm just wondering if my cause of action can just be that SNAP RTO, LLC could not enter into a contract, hence, can't enforce it or "assign" it.