Ahsanallahu Ilaykum. A Google listings company reached out to my business and they have a money back guarantee if they can't get me in the top 3 of Google in 90 days. is this permissable?

Contracting on a result rather than on hours or effort is jualah, and the majority allow it even where the result is not fully in the worker's hands, so long as the fee is known and fixed. On that basis a fee you owe only if the ranking is actually achieved is allowed in sha Allah, and the Hanafis and Dhahiris are the ones who disallowed it because the outcome is not in the contractor's power.