MTN DATA RELOAD

I upgraded my MTN contract 2 years ago but only took a small package and did NOT upgrade to a new device. However, for 2 years now, I am not able to load a Data bundle on my device. I have tried from my MTN app, banking app, MTN store, PEP, and many other outlets but the voucher just can not be loaded. It always says we are unable to perform this reload...... I have sent scores of emails, I have phoned in, I have gone to the store but nobody can solve my problem. This is just getting totally unacceptable because if I leave my house, I have no data to communicate or for my Life 360 to work. So nobody knows where I am. However I can load airtime but nót data. Please help me sort out this bad service from MTN