MTN Telecom Sim Contract

I took the contract in January and in March i lost my one simcard and i called them to block the sim after 2 weeks again i lost my second simcard i called them to cancel my contract and they didnt cancel it when am calling retentions no available consultant i called 1 hr 30 minutes and they disconnected my call. last month they deduction for 3 months and i reversed it .am sending email no respond.BAD EXPERIENCE am even thinking not to use mtn anymore.