In my case, I'd fix the zipper myself.
Or, if a friend of mine told me this problem, I'd replace the zipper for her. But then, I sew. Do you have a friend or someone else you know who sews?
Sometimes you can replace the zipper pull, and sometimes you can't.
(but if that came off through laundering, you really shouldn't feel terribly guilty about it--it's not like you can do anything)
However, it doesn't sound like that's the problem; it sounds like the zipper head broke. In which case, replacement is the only option.