Markham's bad customer service

Good morning my name is Clayton l was owing Markham 2500 and l paid the full amount on the 5th of May they said they were gonna clear up my score in a month and it's been 3 months now and I'm still blocked I can't get a contract phone I can't do anything because of Markham and the problem is they don't even give you feedback you have to call them you have to follow up on them and every time you call them they put you on hold for like 30 minutes and your airtime will probably be finished and they don't care they don't care about their customers