Shocking roaming charges for Nigeria

I was in Nigeria on a business for period 15-20th March 2015.<br> I was billed for roaming charges for 5 days for the excessive amount of R9800.<br> <br> My colleagues who are on Vodacom, had half the billed amount.<br> <br> There are continuous double billing charges on my statement.<br> As I got off the plane for Nigeria on the 22/3 there was a SMS that my roaming charges where R4800, a week later after being back there was another SMS saying I owed R9800.<br> <br> I did complain at the Mall at Reds MTN shop (REQ: ***), nobody has bother to come back to me.<br> My work will not pay my account until all this charges have been explained.<br> I also called two weeks later, still no body comes back to you.