HP technical support is open 24 hours a day 7 days a week. Click this page to contact either French-speaking support or English support. However, your printer is a little outside of the standard support age and therefore it is probably not free. Since this is likely a hardware issue, you may benefit from the upgrade option if you are eligible.
When you say the page has a jagged edge, are you referring to the top of the page?
When you printed the test page after the diagnostic test, you said that printed without problems?
Can you make a copy? If the printer only has this problem when you print from the computer, you may be able to fix it still. If it makes a copy and the paper is still torn, then it is hardware and you could have something stuck on one of the wheels or a misaligned gear.
I hope this helps!