Bogus Roaming in Lesotho

MTN claim I was in Lesotho in April and May 2018 and tried to charge me for roaming calls made in Lesotho. I have never been to Lesotho and I can prove that not one person in my family has been there in the last 5 years. My query number is SR: 1- ********** 8315. I have spoken to MTN many times. I paid my invoice for July excluding the monies for the roaming (it was not on my invoice). I have never requested roaming and my upgrade contract from October 2017 does not have roaming on either- I upgraded to a IPAD. MTN has no documentation where I requested this supposed roaming. Every time I tried to resolve this they send me the itemised billing. So I phoned the people that was called from Lesotho - guess what? not one of them know me and they have never received calls from my number. How does MTN explain this? Further, MTN has now cut my service, threatening not to put it back in place until I pay for the roaming that was never made by me. I fail to see how this is fair. My invoice for July is paid in the full amount I received the billing for. There is also fees dating back one year, that has been added into 60 days. When I asked what that is, I was told by the call centre it is a short billing of 2017 in August. How can they add that now? after 12 months has expired? also, they debit my account, why was it not debited in 2017? I have asked the people on the calls to give affidavits and I can prove with my passport and my family passports that we have not been to Lesotho or out of the country for that matter. I want this resolved.