Open this file in a text editor and paste your Supabase Project URL and anon public key into the CONFIG section near the bottom. The setup guide shows where to find them.
Sign in with the username and password the owner gave you.
Your login works, but the owner has not switched your account on. Ask the owner to activate you, then sign in again.
Only payments typed by hand are on the shop phones. Type what is actually in each phone now and compare. Verified requests went straight to the merchant accounts and need no check.