fraud

I don't like writing bad new here but I just feel like writing, I sold my electric bicycle a couple of day's ago and ofcourse the thing breaks when the buyer get's it home and now she is acusing me of fraud, the damn thing started and worked well when I had it, now she wants the money back before friday, problem is I don't have all of it, I am 27 dollar's short and when I try to explain it to her she doesn't listen, so now what do I do?
I try to explain to her to just wait ten day's but no ofcourse she won't do that.
Just my luck, that damn bicycle is cursed, I tell you that!