Data vanishing

Hi there. I've been very happy with Telkom and have never had issues, so I'm just writing this complaint so someone can please check into the matter for me. I'm on a 10+10gig data plan and have never had to buy additional data as it's mostly just me using it and then sometimes my husband on his phone. Last month (Sept) my data was depleted already on the 24th. I went to buy an additional 2gigs on Sat as I still had to work on Mon - Wed. But by Mon afternoon it again said data depleted. Today the new 10gigs was loaded, but by this evening it said that I've already used up 1.5 of those gigs. It was just me at home and I was sending emails and working online for a few hours. But not enough to add up to 1.5 gigs. Can someone please have a look and see if there's anything suspicious going on? It seems like it might be a common problem in the last month or so. Thank you in advance.