"no answer" on receive

Are you using OEM crg or remanufactured one? If it is OEM, you have problems with laser unit.

Press the DATA REGISTRATION button and press SET. Push the DOWN ARROW to REPORT SETTINGS and press SET to TX REPORT and press the SET key to make the change press the DOWN ARROW until it says OUTPUT YES and press SET. Press the orange CANCEL key when done.

It sound like it was a bad phone line and the fax is missing some of the information. It will look like half of the text was squashed. If it is always consistent check your fax line for crackling and make sure no other devices are active on the line.

Sorry the machine holds 40 transaction and writes over the memory

Scroll through the menus to access "NUMBER OF RINGS"

Do you DSL or any other type of digital phone service?

Try unplugging power cord to get back to AUTO ANSWER

is there toner in the machine ? ( toner spill)
check the manual for the location of the glass, in the maintenance section, if it has toner on it copies will be black or dark, other wise the scaning glass is bad

http://www.retrevo.com/s/canon+7000+manual

Make sure the rear guide is pushed up tight against the paper.

Remove all legal size paper and make a copy.

It seems that the protocol is failing. Just check, by printing a receive report. If there are errors it is after the check frame. If no errors, it is failing before the check frame. In either case, 1st aid is to listen using a handset for noise or static on the line. If the line is clear, then you will have to call service to change the tx/rx attenuation.

Two things: Can you make a copy without this happening? And, Does this happen with certain specific fax number or randomly?