When they kick off about a picture/story about them have you tried pointing out that if it was about you they would laugh ? Or when they are laughing about a photo/story about you then say the same ?

Or just ride it for now cos maybe its because of the way you react they find it fun to push it further ? So try laughing with them ?

In saying all that your story is simlar to mine in that I was used by all of my family but when I asked for help it was no where to be seen. In the end I cut them all off which in ways it has helped but I do miss some of them, the only one I talk to now is my mum ..........

I have lost one brother and three sisters not counting numerous nephews and nieces and in laws. So cutting them off is NOT such a good idea working at improving your relationship is.