Would not be a good practice to directly call gold repo from payment service. In future if there's any new service which requires gold price, would you also make direct calls to gold repo from that service as well? And let's say if there's any change in logic of fetching gold price in future, you would have to update it across all the services which are fetching gold price from repo. That would create a consistency and manageability problem.
Why not have a Gold service which calls your gold repo and payment service (or any other service that requires gold price), make calls to that Service layer. Any logical changes in gold price fetch, update would need to be done in only 1 gold service and all other services are just it's consumers.