in app purchase: receive a error resoponse ,the error detail is "error= Error Domain=SKErrorDomain Code=2 "无法连接iTunes Store" UserInfo={NSLocalizedDescription=无法连接iTunes Store}" , but the user paid successfullly and received a bill from apple , as a developer ,i cannot confirm the bill is real ，how dose the developer handle this user scenario 。in addition the user initiated a refund request on the app store ,but rejected by apple