i seem to be biiled for things i dont know

for the past two months ... my airtime just vanishes .... so on saturday i put R30 airtime .... and last night when i went to bed i had about R22 ... to my surprise this morning i only have R6.26 ... what the hell happened to my money ..... someone better get back to me in less than 24 hrs otherwise im switching <br> <br> thanks hope to hear ferom you soonest