Hi Abi,
Unlike sales process , Service will be done for the Equipment which was sold to customer. In the process you will have a contract with the customer for doing certain Services/Repair for the equipment for certain period of time . You will create Service order for customer only if any complaint is registered at the call center, Unless any complaint registration service order process will not initiate.
If you don't want to perform the service to particular customer, you can restrict creating contract for service.
May I know your business requirement to get clear solution
regards,
santosh