Obviously only my experience, but when my 2nd instructor left suddenly after she got her dream job (she wasn't much over 5 foot so it was tricky!), my flying club found me a new instructor for the same slot I'd booked a week previously.
If your flying club has taken over 2 months to find you a new one, why not try another one out? There are tons of flying clubs/schools out there and I don't doubt the forums can help you decide!
ATB,
K