Retrofit 2 error URL query string must not have replace block

I am trying to call a legacy API using Retrofit 2, this is the URL "/api/0.3/v3/?endpoint=/admin/customers/6728382/addresses.json" and this is the interface method

@GET("/api/0.3/v3/?endpoint=/admin/customers/{customerId}/addresses.json")
Single<GetCustomerAddressesResponse> getUserAddresses(@Path("customerId") String customerId);

However I am getting this error,

"URL query string "endpoint=//admin/customers/{customerId}/addresses.json" must not have replace block. For dynamic query parameters use @Query."

How can I fix this?