MTN bad service

MTN just goes and shuts my phone off with no notification. I cannot call the 135 number, nor can i access the app. Im in a situation where i cannot go through to a branch to find out what the hell is going on. This is my business number that i ported from vodacom and this is the serivce i get now. All i asked is for them to contact me and sort this out as im stuck without a working phone, if i could access the app via wifi then that would help but even the app denies me access