Crazy ex gets in touch via facebook; wants 2 B friends (ie a name for her list); feel dumb. Shuld I block her?

I saw my ex for 2 years; we broke up 5 yrs ago & haven't communicated since. In the last year of our relationship she went 2 Leeds 2 live with her dad while having a gap year; I was in Nottingham for Uni'. She wouldn't want to visit me yet would cry whenever I was late when I'd visit her; I was broke as hell but at least I made it there; I gave up on things like CDs & clothes; she'd cry & her dad DESPISED me for that, "F@@KING EZ'KL" he'd say; I was late a lot of the time but I had things to do; she had money; I'd escort her on her way to buy CDs & clothes. So much more 2 say but no room here. We split up; I was distraught. I'd be with the "why" questions & she wouldn't be straight with me. 2 weeks after break up she'd call to mock me, humour me & gloat, sometimes with her friends in the background laughing; went on for about 2 months. I got sick of it & cut her off. 4 months ago on facebook, she wants 2 B friends & adds me on her list; I feel stupid now; Should I take her off my list?