MTN stole my airtime

I had over R100 airtime on my phone yesterday (22 June 2020) and my employer Grahamstown HOSPICE loaded a further R200 on 22 June 2020. I convert this airtime into data as I require it because I am working from home. Today 23 June 2020 I have no airtime...where has it gone MTN. How am I going to do Hospice's work from home.