As someone who plays Defenders and Corrupters which do not heal, I feel for you as I have been there before. 😢
I normally put something sarcastic in my bio which states "I do not heal, so go heal yourself". If I get hassle, I kindly remind them to read my bio and I tend to give them a one star and never team with them again.
Also, when I do play as a healer, I will not run after someone who needs healing. If they die, then that's their fault and not mine. My job is not to chase your ass all over the map just to heal you.
I also tend to take TP just in case I need to heal someone, as I will TP them to me. If they get annoyed, then they need to be prepared to die a lot more, as I won't heal their ass in future.
