call center for outsourced services

I do hope this forum serves its purpose.
Many a time we come across outsourced projects which essentially do not go well either with the vendor or with the provider of such services. how does one justify the deliverable results from a service providers point of view. does anybody have an answer.
although we run a 25 seater centre, we are forced into accepting projects which sound weak.
do write in to speak your views.