Data Issue

Since moving into a new area - both my Telkom wifi router sim and cell phone sim's internet activity did not work. No connection ever. My cellphone sim is now working (changed carrier to MTN) but my other sim was still not able to provide ANY internet. Imagine my surprise when browsing my telkom invoice it states I was using data (2 - 5mb) daily, I probably only used the router twice in April when I was in another area but definitely not daily. I accept that I pay for a set 5gb contract plan - but I do not understand why on itemised billing does it reflect I used data when the router was off.