Perplexed again

I had a flu vaccination on the 17th of May. I need proof today that I had a flu vaccination.

One would think this is a straightforward request. Ask my medical aid for proof that this was a flu vaccine. I have the date, the amount everything.

Yeah, they cannot. There is no way in hell they can send me any kind of proof that this claim was for a flu vaccination. They can even confirm the nappi code via chat, but there is no way of sending me any proof by email...

Imagine I need help with something more complicated than that!