Frontier Communications They will not give me credit on my bill for the day I moved out and returned the merchandise the same day Internet

 I lived in a Home owners community where they provided exclusive TV and Internet services.

Those services were provided by Frontier Communications.

I notified them in February that I was moving on the 15th and that I wanted to return one of the cable boxes. I was sent the return box and I returned the cable box

 As I stated I vacated my home at 3311 Mercer Road and the new owner moved in the same day.

On March 14th I returned the two other cable boxes and Frontier has acknowledged those returns.

However, I am recieving a bill from Frontier for the Month of March 10 thru April 9.

I have called several to plead my case and they still want to charge me until March 26th even though the merchandise was sent back on the 14th.

In the meantime the new owner who also is bound by Frontier will be paying for his services from the 15th Of March. That is double billing. they are a bunch of crooks. who can I report this to?