MTN Unable to resolve my issue

Good day. For months now, after I activated a MTN datashare, my Samsung S5 don't give me most notifications anymore. This occurred exactly after I enabled the datashare function. I only get notifications when stepping in a Wi-Fi zone or sometimes when I open the actual application. I went to the MTN service centre (a couple of times) and they did not know what it is. I then got a number 1555. I phoned that, in hoping they can help resolve my issue, but the person were very curtly, unfriendly and unhelpful. I've been a member with MTN for more that 13 years now and think of leaving MTN, because of the service and the constant issues I'm having. I also had a big data issue, where my data just disappear. My wife and her colleagues still have issues like this, were she have to keep her data off at all times (all updates turned off). At this point, I'm very disappointed at MTN.