I would like to hire a Weebly expert to solve a problem on my webstore

I run various classes which can be booked through a weebly store ([login to view URL]). However I need some way that people can join a waitlist for a particular class if it is sold out or unavailable (or if they can't make the scheduled time but could tell me when they could make it). Their inputs (name, email, course, comments on availability) should be saved to a google spreadsheet or similar. I need this waitlist process to be easily replicable on all of my many products. I have buggered around with pop-up forms etc but need an expert to set up the simplest and most effective solution. There are various other things I could then ask a weebly specialist to look at if I was happy with them.