Alltel Continuous Escalating billing on a deactivated service I cancelled due to unemployment. Little Rock Arkansas

My husband has been unemployed since January, I am temporarily unemployed. We both were recently hospitalized, so we are strapped fiancially with medical bills, on top of normal basic living expenses.
I called Alltel customer service early May to tell them that we could not pay for our service and to cancel our service. The lady on the phone said they would cancel our service.
Within a few days, we had no cell service, yet we are being billed consecutively each month, even though we are not under contract with them. Our contract with them expired in February and we can freely chose another cell service.
I called Alltel to complain about the continuous billing. She said the person I talked to should have explained how it works. According to them, they can continue to bill us, even though I requested to cancel and we cannot pay the bill.
We are trying to work with our creditors regarding our situation. Alltel did give us a $200 credit in February. We appreciated that very much. Now they won't work with us under such trying financial circumstances.

Bhonest
Hamilton, Montana
U.S.A.