MTN airtime disappears

That one star rating is a lie since I cannot review without it. MTN is *****ing money from me every time I load airtime. It so happens that before I can do anything with it R1.95 disappears. There are no subscriptions on my number and I have called them numerous times to ask what happens to my money. They can only see that I have loaded the airtime and not why my money disappeared. I have had it with them truly, I went from contract to prepaid because of their dishonesty, no I probably will have to port my number.