You could write a letter to IRCC explaining that he doesn't want to give you one and that it's because he wants to tie you to this position/company.
I've heard reference letter is a must but I could be wrong @legalfalcon
No idea, I've been trying to find a thread for that and it seems like there's only ones for people submitting it via mail.
My picture got refused via the portal and then I had to resubmit it on Aug 18th and I haven't heard back since then.