MTN shocking service

I am currently in the UK and took out a contract for my son of 16 while he is in SA. They have charged me over R3000 for his contract when I signed up for R450 a month with gigs and airtime included. I was **** to by the store with my previous phone saying if I put another sim card in my phone it would still be covered and when I claimed I was told no after paying the highest premium. Now after numerous emails of been redirected still no feedback and my sons phone has been suspended. He is having a major heart check up today and I cannot get hold of him. MTN your service is shocking. I want an answer urgently as to what is going on.