playful joking is alright (whether this is throwing insults at one another.. just normal as kids, especially when growing up together)... but when things are getting too much and it becomes an emotional strain on yourself, then you can really determine whether they are true friends or not..  it really shows their true colours if they show no empathy to your emotional well-being..

seems like it has been happening for some time..

if you have asked them to stop on multiple occasions, yet they continue, drop them... they are not good for you and for your general well-being.. true friends are there for one another.

there are PLENTY of people in this world, don't resort yourself to those who don't care.. waste of time and you have better things to do and other things more important to care for in your life! you can make new friends very fast, move cities, get a new job and find your ground don't get stuck with these guys.. whoever they are.