MTRMultiStoreGatewayService is a software product for Windows developed by More Than Rewards Inc.
It is reported that the following Windows processes are part of MTRMultiStoreGatewayService:
If you want to remove MTRMultiStoreGatewayService from your computer, just go to Start > Control Panel > Add/Remove programs and select MTRMultiStoreGatewayService from the list of programs.