Mtn data messages spamming

I am constantly getting spammed with messages from MTN telling me my data bundle has been depleted or is 50%/80%/100% used - i am on the 2gb pee day for 30 days bundle and once i use up the 2gb per day, Mtn spams me with messages over and over - even through to the next day when the new 2gb is loaded. I changed all the settings in my Mtn app, used the *135* ussd code to disable data notifications, etc, yet still i am receiving messages from Mtn. In the last 24 hours I have reveived more than 30 messages from Mtn on this issue, and the Ussd menu constantly pops up. This all happens even during the night when i'm trying to sleep, and during the day when i'm on a call and then these messages and popups come through. I am sick and tired and disgusted by this spamming and want to be unsubscribed from all marketing, data, and any other notifications from Mtn because it clearly means nothing to have all those options in the Mtn app to disable these things as well as the Ussd codes that are good for nothing because they don't work as intended.