Turkcell Used Up My 3GB Data in 15 Minutes Without Significant Usage

It was around 11:40 AM today when I bought a 3 GB internet plan from Turkcell for ₺160. I only used WhatsApp to check my messages, and after only 15 minutes, I got a message telling me that my extra 3 GB had been used up. I had to wait a long time to get through to customer service before I was told it was because of a "update." What does Turkcell think this means? How does 3 GB go away in 15 minutes when I haven't used much data? It seems like my money is being wasted for no good reason. I didn't think Turkcell would do this, and I hope they fix it quickly. If not, I'll think again about my mobile service choices.