How to stop needing and contacting ex-friends?

my friends are not really my friends. they are in relationships and never contact me. i am very lonely and it's causing me great anxiety. I need to stop myself from contacting them anymore, but I keep feeling the urges - and I don't want to pive-aggressively act out. One of them has my apt keys and I want then back, but don't want to deal with her. Please help - what do I do?