Confusion Over New Billing/Integration Structure for Managing Clients

Apparently there has been an update to the billing/integration structure, and now I'm completely lost as to how I'm supposed to manage multiple clients. Before, I could integrate/de-integrate between projects as needed. I build while on the free plan, and then switch to paid in order to publish. Now it's only letting me integrate a single store, even after de-integration/cancelling the unrelated store (image attached). Can I not have one store on a paid plan, and another on free? And if the solution is to pay for the plan with 3 simultaneous integrations, then why is billing handled through the client's Shopify, and not on my end? Surely the intention isn't to have the client pay for my other client's replo integrations. The link to switch to stripe payments takes me to a blank page with some code on it. What is the intended design from the Replo team here? It's a little convoluted and unintuitive unless there's something I'm missing. Very confused and time is burning while I'm unable to integrate and work on Client 2's build.