What to do with this 'friend'?

ok so i've a friend who is constantly complaining and constantly telling me her problems. and i try to help her with every single problem she has! i listen to all her complaints and stuff. and whenever i have a problem, she changes the subject. this one time i told her that i'm so upset abt ____ ..and i kept saying i'm so upset cuz i really was.. her response was 'hahaha' or lol. thats all. and then she changed the subject about something else. and i was like u really don't care about my problems do u..and she was like i do..and then i was like i have to go bye. and then after that, she messaged me, we had a really small convo. and today she wants me to call her(she doesn't have my new #)..i really don't wanna talk to her. idk if i should or not cuz shes making an effort to talk to me. but this happens every time. shes basically never there for me & thinks her problems are like the worst problems ever even tho they are common parent problems.