If the customer does not have enough credit, the service flow is as follows:

1. The customer requests the service (just like in the previous flow).
2. A service provider gets the request and asks Odoo whether the user has enough credit. Suppose that the customer does not have enough credit.
3. The service provider returns to the customer and informs them that there is not enough credit in the account, showing information (an Odoo service packs link) on where the user can purchase the service.
4. The customer is redirected to Odoo and purchases the credit for the service.