R120 000 billed and no response

I went to 5 different MTN shops between Middelburg and Witbank and asked if I could use my contracts 500mb monthly data in South Korea between May 11-12. Some said yes and some said they don't know so I called costumer care on May 12 and the person said yes and I must use Whatsapp but if the data is finished roaming cost would be high.I knew I had a R5000 limit on my contract. In Korea I used approximately 50MB at most of what I can remember I had 4 short Whatsapp calls and sent messages on Whatsapp. I used my phone between May 16 -22(MTN was on a strike) my phone was blocked by MTN that week. The end of June we got a bill of +R120 000. This is not at all possible with the limit and the amount of data I used. We called customer care a lot of times for information with no result so I started to write everything down. July 29 called customer care ref no.*** she said that there was no quire locked and she locked one again. On November 5th this case was given to MBD Incorporate (also waiting for mtn to pay R3220 to them as agreed ***. Our legal adviser said we need the recordings, contract and bill to go to court and again we are not able to get this. Help!!!!!