Termination of Account

I'm tired with tracker and their pathetic service. I have been trying to cancel my so called month to month contract since April after my 36month contract expired. I have phoned several times and have been told that their retentions department are an outbound call centre and are very busy. Till this day am still waiting for their stupid phone call and don't understand why can they not cancel the dam contract. Really this is not on, system that you are using is useless.