So much for contract cancellation

MTN is a ****. I took a contract of a rooter + data for 24 months. When time went by the rooter's battery got swollen and did not charge I couldn't use it. I do not have a dual sim card cellphone where i can maybe put this sim card and use my data that i pay for every month. I decided to call MTN and cancel my contract I was told i cannot cancel before the end of 24months otherwise i must pay penalty fee (such a big amount) I was shocked. Basically they are saying i must pay the full a month for the 24months which they have given me data for few months, THAT"S *******!!!!. IM so upset. I know I signed a contract with them but circumstances may change along the way of the contract and things happen along the way and a customer is sometimes forced to cancel the contract. MTN doesn't have to charge so much for cancellation its unfair to the customer. They are ******** people period!