Product: Debt collection

On XX/XX/XXXX, I got a XXXX promotion via phone for 3 devices and 3 lines for those devices. 2 Of the lines would be transferred from XXXX XXXX XXXX. The contract cancellation for the devices and the lines was free of charge ( no penalties and cancellation at any time ). On XX/XX/XXXX, I called XXXX Customer care to cancel the process and they told me that was no possible since the devices were in route to my address, and the only way to cancel the contract ( devices and lines ) was to not receive/accept the devices and the courier ( XXXX  ) would return them, then XXXX would automatically terminate the contract and refund everything that I had paid. I also went to the XXXX physical store and they stated the same. So, I did refuse to receive the devices and on XX/XX/XXXX, I got an email confirmation from XXXX indicating they had started the refund process, and the same day, I got another email stating they had received the devices. On XXXX XXXX I got another email from XXXX  indicating the refund amounts for each device had been processed. On XX/XX/XXXX, I received a letter from XXXX stating I owe them XXXX and it was the final notice, even though I never received any other bill before. On XX/XX/XXXX, I got another bill from XXXX stating I have a debt of XXXX and the lines ( phone numbers ) involved. I called to XXXX Customer Care to clarify the error and they told me the account was canceled already and they needed the PIN code, I gave them the PIN code and the system didnt accept it and they told me I needed to go to a store to restore the PIN and call them again once I have the account PIN code. In XX/XX/XXXX, I went to the XXXX Store and the representative told me they are not able to restore the PIN and the very same day I call XXXX customer care again, and they told me they should be able, at that point I was very frustrated because the representatives at the store were assisting other people while I was waiting for them and talking to the XXXX customer care person, at the end the person from customer care told me she had talked to her manager and they would send an email to billing department to see why they had posted the charge since the beginning even when I did not receive the devices and they never removed the charges after the refund was processed, I was okay with that and asked her for a case/ticket number, so I could do a follow up, but they told me it was not possible because everything would be via email, and they can not generate ticket/cases ids for that, at the end customer-case told me they would reach out to me via phone on XX/XX/XXXX at XXXX CST. On XX/XX/XXXX, I received another letter from AllianceOne stating I had been sent to collections for a debt that I owe to XXXX  for XXXX. In XX/XX/XXXX I went to the XXXX store and called to XXXX Customer care again at the store and they told me I needed the PIN code, I explained the situation and handed over the call to the representative at the store, after they talked, XXXX customer care hanged up and the representative called to XXXX customer care again, but now via an authorized line, the store representative and XXXX customer care stated it was strange that I got charged for something I never got and used, they also stated that what I was told about the automatic cancellation is not true and they dont have any records that I had tried to cancel the services but the service/devices were canceled. They told me they can not do anything and that I need to contact the debt collector and prove to them I canceled the services and XXXX can not do anything else at this point.