Unauthorized airtime contract

I received airtime from "Jet" and when trying to enquire about it I was sent from pillar to post and when trying to do sim swap i was told I should contact RCMS as they say I have contract with them. But I never actually agreed to any contract with them. I then contacted them and they said they are logging a query for me and they will get back to me but they never did. I phoned them again after few days and they told me that somebody phoned me the same day i logged a call but in actual fact I never got any call or missed call from them. They logged another query and again gave me another reference number and said they will call me, again they did not. Today I phoned again and they logged another query with another ref. Now I still can't do sim swap before they give me permission with a letter or something. Reference no. I got from them are as follows: ********** 395453; ********** 397123; ********** 397113; and ********** 401181. I'm now tired and frustrated. Please help.