Credo Mobile CREDO stole my money despite the fact I returned phone within 30 days. SF Internet

This winter, one year into my two year contract, my CREDO Mobile Samsung phone died. So I was eliglibe for a new program with an IPHONE. I was not sure I would like the IPHONE, but they assured me if I wanted to try it for 30 days I could with no risk.

Within a few weeks of receiving a phone and new contract from CREDO, I wanted to cancel.  

I confirmed with CREDO customer service that I cancelled a new phone and the contract within 30 days in order to avoid cancellation fee.  The first call I made to cancel was within 30 days and they confirmed this and emailed me the mailing label to return the phone.  I did this.  I noticed a $428 charge on my phone bill and called again.

Again, CREDO Customer Service confimed that I had cancelled the contract within 30 days and they would send this to a Suprevisory Department to verify and cancel the charge and call me within 48 hours, which they never did. Instead they just took the money from my checking account.  

So I called again, and went thru Customer Service and then onto a Supervisor. The Supervisor looked at the case again, and saw that he said, looked like I "had called within the 30 days to cancel" and would sent the case back to the Supervisory Department and they would call me with in 48 hours.  Well they have not and it has been 72 hours.  I don't think they will be callng nor refunding me my money.

Also, for some reason, I got signed up for a service called Credo Longdistance.  I do not have a land line, yet, they were charging me about $30 bucks a month for this service.  This charge started about the same time I called the first time to confirm my cancellation and get the mailing label to return the IPhone.  

I think when I called to cancel, the original Customer Service employee made some kind of mistake, and now I have to pay!