Testing a $39/month office-hours tier to see if it produces a second payment

I have 14 people through the course since March and almost none of them have bought anything twice, which is either a product problem or a me problem and I can't tell which yet. So for the next six weeks I'm opening four slots a month for a standing 30-minute call, $39, capped at 8 people so I don't drown. If recurring revenue is the goal, someone has to choose to pay me a second time before I go redesigning anything.