Cancellation and Customer Service (which is not even there)

I really hate this company they are pathetic; I have cancelled my contract on february 202 and moved to pay-as-you go; but they still sent me a bill for the Month of March and yet I do not have the contract benefit I used to have, because I am now on pay-as-you-go. Their call center and self-services are just usless. This company is still money from people; you guys are corporate theives