Same question: you're trying to build what case? Trying to achieve what exactly?

Just FYI, as a (former) employee, you almost always get the short end of the stick.

They may or may not issue a reference letter. fatmanfilms is right, for employments < 1 year, there's usually just a confirmation of employment, but no full reference letter. Regardless, you are entitled to one if you insist for some reason. It's not as important as people make it out to be though. It's up to you whether you really want to spend the energy (and possibly money) to get something that is of little use anyway.

I agree with 3Wishes approach. Write your own, send it to both HR and former supervisor, registered letter, tell them to return within 7 days. Give a copy to RAV too, just in case; they probably need it for their files.

And btw - the rest is corporate reality almost everywhere. Nothing unusual.