Difference between repository and service?
A Repository is essentially a facade for persistence that uses Collection style semantics (Add, Update, Remove) to supply access to data/objects. It is a way of decoupling the way you store data/objects from the rest of the application.
A service supplies coordination or other "services" that are required to operate your application. They are very different in that Services don't typically know how to access data from persistence, and repositories typically only access data/objects for any services you may have.
The repository is where the data is stored. The service is what manipulates the data.
In a real-world situation comparison, if your money is stored in a vault in a bank, the vault is the repository. The teller that deposits, withdraws, etc is the service.