If you open the ContactT does the record exist?
If so what is its CustomerID (foreign key)?

Make sure you Refresh the record before opening the report. If the little pencil is still showing in the record selector, the record is dirty which means it hasn't been saved to the table yet. The report won't see it. Refresh then Open Report.

Fixed! Just had to put the default value on the combo box as Forms!CustomerF!CustomerID and confirmed that it did come through on the report with the name and all coinciding fields.

I've very quickly learned not to skip around your videos lol. Makes for a terrible time later.

That was going to be my next question. That's how the link gets made. :)