Hello there binkiboogle, Welcome to the Forums! I hope you enjoy your experience:)
I saw your post about the Carriage Jam issue you are running in to with your Deskjet 3520. I do have a troubleshooting guide that I would strongly suggest following and I do understand some steps will look familiar. Go through the steps you haven't attempted and try them out!
A 'Carriage Jam' Message Displays on the Control Panel
If the troubleshooting does not help resolve your issue, I would then suggest calling HP's Technical Support to see about further options for you. If you are calling within North America, the number is 1-800-474-6836 and for all other regions: click here.
Have a wonderful weekend:)
Thanks for posting in the community!