Can't receive channels 17-47

Six weeks ago my Tivo series two stopped showing channels 17 to 47. (It shows channels 2-16 and 48 - 99.)I have the Tivo hooked up directly to the cable. I unplugged the cable from the Tivo and put the cable directly into the TV and the TV gets all of the channels. After calling Tivo for help they suggested and I reset the Tivo line up and made sure that channels 17-47 were checked and still have gotten no reception on those channels. I had the cable company come out and make sure the signal to the Tivo was correct. They said it was. I put a line amplifier on the cable signal and it made no difference. Any one either have any ideas on what else I might try?
Thanks