Cloud & Tidwell ERC, AmSher, Allied Interstate four companies conspire to collect 1 debt? How in the world did T-Mobile allow 4 different companies to use it's name to collect 1 debt Birmingham, Alabama

  After terminating my T-Mobile account I received a hyper inflated bill from them, when questioned they immediately sent my account to collection.  The first to respond on behalf of T-Mobile was Cloud & Tidwell - very impressive and legit looking invoice with the usual collection demands within the body of the threatening letter.  I responded that I would be making small monthly payments until paid.  All of this I did, my payments were made with a postal money order attached to my letter with the new reduced balance.  This went fine, I paid my debt which was $165 according to their letter.  Only later I discovered that another company - ERC (Enhanced Recovery Co) was actually on my credit report and was supposed to be the company T-Mobile contracted to collect my debt of $100.01. 
  When I contacted both ERC (as instructed by T-Mobile) they had no useful information or answers. So, I contacted Cloud & Tidwell since they are the ones that I paid.  A third company, AmSher responds saying that they collected $65 which was owed them.... and so, what happened to the rest of my money? Cloud & Tidwell who collected all $165 hasn't given me a paid in full or anything!
  To add insult to injury another company Allied-Interstate is now attempting to collect on the very same debt.
Is there no end to the shameless and unsavory disregard for peoples lives?