Charged for 40/40 line and barely get half the speed

We were told that 30/30 line is becoming a 40/40 line.Our speed has never been 40. Since a week and haf ago, the speed dropped till sometimes 2.5 up and down. I checked this morning again.It was 14 download and 22 upload speed.They keep teling us to check with an ethernet cable.Why don’t they just send a technician out to check if there is something wrong/damaged cable etc.Why must I pay R720 per month for internet speed that I never get.Internet service is shocking!