Hi,
It's difficult to size this project without any more details, but I'd be happy to take a look. If it's just a couple of functions that are giving you trouble, then a $100 should cover all the work and it could be a fun debugging challenge. I've broken this down into two milestones: $20 for going through your code and design & understanding whether your tech stack is even suitable for the problem you're trying to solve, and $80 for solving the errors you're getting if that's true.
I've put the delivery at 14 days since I'm working full time as a dev, and just doing freelancing as a side gig in the evenings.
Regards
Sander