This is done on the web, by the company's owner; the phone app has no plan or payment screens. An admin sees the plan and what it has used, and is told only the owner can change it.
Open Settings, then Plan and billing. It shows your plan and its price, its status (for example Free trial, Active or Payment failed), the next charge with tax, your card, your invoices, and what you have used this period.
To change plan, choose one under Change plan (monthly or yearly). Before anything happens, Supligo shows exactly what it does, in Stripe's own figures: - A bigger plan starts now. You pay the difference for the rest of this period: what is left of your current plan is taken off. Its limits open as soon as the payment goes through. If your bank asks you to confirm the payment, or the card is declined, your plan stays as it was and Stripe's page opens to finish it; unpaid after 23 hours, the upgrade lapses and nothing is charged. - A smaller plan starts at your next renewal. Until then you keep what you paid for. You can keep your current plan instead, from the same page. - During the free trial, a change is made at once and nothing is charged. The trial ends on the same day, and the plan you chose last is charged then.
Update card opens Stripe's secure page for your card; Supligo never sees it. Each invoice opens on Stripe, with its PDF.
Cancel plan ends it at the end of the period you have paid for; in the trial, at the trial's end, and nothing is charged. Until then everything works, the page says when it ends, and Keep my plan undoes it. After a plan has ended, Supligo asks you to choose one again; the free trial is only once. Nothing is deleted, and you can download your data.
Payment failed? The page says Your last payment didn't go through. Stripe tries your card again; update it, or pay the open invoice. If it is still unpaid after 14 days, Supligo pauses the account: your storefront closes and nothing is sent to your customers, but nothing is deleted and you can still download your data. Paying opens everything again at once. While a payment is failing, the plan cannot be changed: pay it first.
A smaller plan must have room for the customers who order from you now. If more order than it allows, the change is refused and says how many: put the ones who no longer order On hold first (the customer, then Edit) — nobody is removed, and their orders and history stay — then change the plan.
Still stuck? Signed in to Supligo, open Help: ask your question and get an answer in seconds, or talk to a person.