alshamil internet / high amount bill

we have alshamil line at our shop using since 6 months at paying an monthely amount of 280 dhs but from july we git bill more than 500 as extra and also after august we got more than thousend, regarding this issue i called costemor care two times to know what happend but the didnt give detailes told me to check online when i check also i didnt get detailed bill this is not fair