Bad to no Internet for two months

When we had our modem installed the guys left here and we had no Internet connection but only when we connected through a LAN cable. We phoned the call centre with little to no help. We keep emailing the call centre and get no reply. They also double billed me and added extra services which was not part of the package agreement. I emailed them more than a week ago and still have not gotten any feedback. If you want to be worse than your competitors then I guess I will have to go back to them.