hp OfficeJet 6300 won't receive faxes.

Gift for 80 yr old stepmother. Then gave gift of a new at&t cordless phone w answering machine, because she had an old dial phone and old answering machine! Tried adjusting the number of rings so Fax would pick up before Phone. Didn't work- with new phone, Comcast voice recording took over. Asked Comcast to cancel their Voice answer, they did. But still it didn't work. HP sends fax fine- sends electronic pickup fine.

Cable, Internet and phone are by Comcast. (She has ONE phone line, main/fax with Comcast. Has a cell phone via at&t.)

I completely trust hp and at&t. I completely DON'T trust Comcast. But I don't know enough about technology to challenge them and I can't resolve this issue myself. I can't make calls during the day and I work overtime. AND my stepmother is completely technologically challenged and frequently uses incorrect/wrong terminology.

Can't believe I'd have to get another phone line just for fax- she does small real estate stuff, no heavy duty use.
But if I do, I want to know this. I can't believe this is a hard TECHNICAL issue to solve. But it only takes one customer service person to misdirect/screw-up innocent technology.

Will offer $50 for a straight answer from someone who knows. But so that I may finally be done with this issue, I will offer an additional $100 if this problem can be fixed over the phone.