No service at all

I am not happy being an mtn customer anymore I recieved a message that I now have to pay more for my contract which I signed for to pay R699 per month I was told this is not allowed because I got this Samsung s9 on a special honestly mtn has no service I do suggest people rather go to vodacom as they could assist me when I was struggling with my phone and mtn is not helpful at all to be honest I chose this phone because it had worked with a game I like to play everyday which I am now still struggling with so I personally feel I should not pay more for not getting any service at all.