Lost and Frustrated

Called Comcast to get my issues on our account resolve. Currently paying $136/month on, according to the bill, 30+ channels and download speed of 100mbps. The 2nd person i spoke with (customer solution) said we should have 100+ channels and up to 300 mbps speed. She transferred to a 3rd person and told me to tell them to replace all my equipment. 3rd person was getting ready to ship the new equipment but said billing dept is not letting her and put me on hold. 4th person pick up and i had to explain again my issues. Been on the phone for about 50minutes with Comcast and no solution to my issues. 4th person says he cant send me a new modem because there is a hold on my account - the hold note says my internet package need upgrade. My internet is not working, i am only getting 30mbps and in and out all the time, and yet, they want me to upgrade? How much more do i need to spend with them monthly to get a decent product/service? Does anybody know anybody that can help me with these issues?
I would very much appreciate any help.
Thanks,
Mailin