Dishonest and Un-ethical

Dishonest and un-ethical company. In short, I requested early termination fees from MTN to close all my accounts, paid all the quotes received in full and within 24 hours. 3 Months later this Dishonest company tells me sorry, MTN made a mistake you owe us… Now they deduct double the monthly subscription with no apparent reason why and refusing to correspond with me (Why respond if the customer is leaving anyway right).