MTN data contract - cannot buy additional data directly

You take out a data contract with a ****le. MTN App does not allow data to be purchased. Banking APP try and purchase MTN data, the number is 'not registered' Try and share data form your own phone, cant be done. Phone the store where I got the contract, state I must buy air time and convert the airtime to data. So how do I talk a 76y/o lady who works remotely for me to take out the sim card in the ****le, take out the sim card in her phone, put the ****le sim in her phone ........, while not being able to talk to her??