Network provide @ its best

Being a MTN user is not a problem, but the treatment one gets from the contact center is appalling, I have been trying to upgrade a number I have not used in 2 years + but have been paying the contract monthly without fail only to be told I can't upgrade due to a deactivated line and non payment, only to be told in another department that my bill is paid ( in advance ) and the line is active. This is a problem I have been battling with for the past 3 weeks hoping MTN would solve it but an advisor now and then would " assist" by re activating my line only to be told in the Sales department that my sim/line is deactivated. If I were to refer someone to a network provider the MTN brand would be one of the last as they are allowing contact center advisors the leeway to treat customers as they see fit and not per business standards if any.