What should I do?!

I was good mates with this lad literally just mates and he liked me and apparently he went around saying he wanted to shag me but who told my boyfriend always lies and we had a massive argument about him blocking this lass cause he was talking weird to her like more of a mate so he blocked me in front of my eyes and then I found out he unblocked her and changed her name to izzy and said it was his cousin I then remember him telling me he’s meeting his sister he lied to my face and said he was meeting his sister when really was planning on meeting her