Distraught single mom of 2 boys - now out of work because son used phone without my knowlege - Vodacom not able to help!!

My 10 year old son managed to use my business cell phone without asking me, and ran up an out of data bundle charge of R7500 for the month of March. I didnt receive an invoice until I went into the store and asked for one. I was informed in store that there was another R5000 ready for the month of April as 50 gigs of data had also been charged for the month of April. I have phoned and spoken to several call centre operators for their assistance to get the R7500 out of data charge for March converted as if I had bought a 10 gig package but have been repeatedly told that this is in no way possible. I have begged and pleaded as I have now lost my job over this, and being a single mom of 2 boys there is no way that I can pay for this. I have no idea what to do and am shocked that Vodacom are not able to help with converting to a bundle rate - Everything is digital!! This has never happened to me before and I have been a loyal supporter of Vodacom for a very long time. I cannot believe that nothing can be done. Yours very Unhappy and Stressed out of my mind Joanna Dunsby ***