Cant purchase data bundles.

I have been purchasing data bundles off my Nedbank App for the past 10 years with no problem. I tried last night a well as this morning, to purchase a data bundle. Both off my cell phone and laptop, but to no avial. I get a message that the "service provider could not process your request". I phoned Nedbank and they checked all OK their side. I phoned MTN, to be told to download the MTN app. I DONT WANT the MTN app. My phone is full of app's that I do not want. The marriage between MTN and Nedbank have worked successfully for years? What has been upgraded??????