Airtime disappearing

Alright so checked my airtime balance this morning and all my airtime was gone called the Call center and spoke to Sindi buthalezi right so they telling me that I used all my airtime on the internet right so why this doesn’t make sense I’m permanently connected to wifi at home and the I also have a mobile router that I carry with me so that I don’t have to use data or airtime on my phone so firstly the so apperant senior that I spoke to was dam rude they said they will escalate it to find out where my airtime went they saying I used it at 4:55 this morning I was still sleeping by that time plus this isn’t the first time airtime is disappearing.