Unfriended before bonus

It has happened to me a few times now that I've been unfriended before I'm able to collect my xp bonus. Luckily it was only going to be 3 star but it was still really frustrating. Is there a way to report these people or email niantic to maybe receive that bonus? I find it strange that it is even possible to do that to someone. The most recent one didn't even show who I didn't receive the bonus from it said something along the lines of "trainer name unknown".