XtraTime Popup keeps my screen on the entire night and drains my battery!

I have been trying to get assistance from MTN on all their channels with no luck! Every morning I wake up to find that there is an Xtratime loan popup on my screen and it has kept my screen on since the middle of the night. I then wake up to a flat battery. Surely this is harrasment, on top of the forceful popup i also get smss at 2am telling me that my airtime is low. I just spoke to an agent now who says she cant do anything about it and that i should dial 155 which doesnt work!

If i want airtime i will buy it, how is it ethical for MTN to hijack my device and harrass me in the middle of the night just because my airtime balance is low?

All my marketing setting are set to NO but at this point I am forced to either sleep with my phone off which is not an option as I have a small child that I dont stay with and need to be available at all hours or I am forced to buy airtime or I am forced to have my device and its battery possibly damaged by having the screen on the entire night! PLEASE SWITCH OFF XTRATIME LOAN MARKETING ON MY DEVICE, I DO NOT WANT IT AND I DO NOT NEED IT!!!!