CellularOne Dobson Continues to debit my account after service canceled McAllen, Texas

When CellularOne sold their 405 area codes to ATT, they moved the 580 area code office to Weatherford, Ok., which was inconvenient to my location. I kept my service until after all the contract expired.

In January I canceled my service with CellularOne and chose a different carrier. I notified CellularOne of the cancellation of service.

CellularOne continues to debit my checking account 155.56 each month, after continued attempts to stop service.

My last conversation, they told me they had no record of my notice.  I would have to come to the closest office to cancel service. The office is 57 miles from my home.  I would have to take off work to do this in person. 

 CellularOne acknowledges no activity on my account since January.  As of date they have debited my account 933.36.  They deny owing me this amount since they have no record of me closing the account. 

I have stopped payment through my bank which will cost me $25 each time they attempt to debit the acct.

Any ideas what I should do next?  Take a day off & go up there?  How do I get reimbursed?