I want to cancel my contract

*** Im very disappointed with the service i received from call center including the manager(olleta) who was on duty that day I called in yo cancel my contract as it was due and they gave me a ref no and i was told that retention will give me a call to cancel the number Till today i haven't received a call and my account will be billed but i did everything on time Please assist to refund my account as i did cancel on time to avoid being billed Ref***, ***