WORST after-sales service!!!

This must be the worst service provider ever!! The after sales service is NON-EXISTENT!!! They always say that they will schedule a technician to come out and that the Scheduling Department will contract me to confirm the time. They NEVER call back and they NEVER pick up when I try to contact them!!! I have been without internet for 3 weeks. I have been on the phone with them for hours!!!!! NOTHING IS WORKING!!!!!!!