Missing data HOW DO I FIND OUT WHERE 80 GIG'S WENT !?

I have been with Telkom through Afrihost for a while now and I was very happy. The 80+80 was more than enough for my Zoom meetings, FB, WA, Candy Crush, YouTube and weekend Netflix. The signal was strong. No issues. I have 3 devices. I am 54 - not a gamer. UNTIL mid August ! My connection was lagging. I was on their WhatsApp trying to find out if Telkom was down etc. Nothing. No help. Re-booted. I was loaded with my monthly 80 Gig on the 1st September. That 80 gig was GONE !? They say I used it ! ON WHAT!? I wasn't even watching Netflix !? HOW DOES 80 GIG BE USED IN 10 DAYS!!!??? I work remotely - to buy top-up is double the price of the "contract" AND THEY SIT THERE WITH A MOUTH FULL OF TEETH ! BLAMING ME ! NEVER EVER TRUST AFRIHOST OR TELKOM ! EVER !