Upgraded to 100 Mbs down and only get 20-32 Mbs down can someone please look into this

Upgraded to 100 Mbs down and only get 20-32 Mbs down can someone please look into this I read some post where you fixed it.

I have called with no help they have me reboot a lot. They are sending a tech out but I don't think that is going to fix this issue.

I have a doc 3.0 modem. It has been registered and activated.