I won't mention names but one of the biggest problems I encounter in the outsourced industry is low quality firms. That's aint a secret, there are too many small low quality companies and those offering horrible service (communication, English, solving issues (not solving), instability of other kind..). And sadly, those companies creates a more general, more global concern among the customers (companies). Lately I had a call with EU based customer, he wanted to hire a dev / Linux expert and he told me "Tried 15 outsourced companies and all failed to deliver", now those 15 companies created for that customer an impression that he no longer willing to outsource at all, he simply fears that same would happen with every single outsourcing company and that hurts those companies that actually provide a high quality service and in fact, there are great companies, wonderful teams and amazing talented people out there.
To avoid the same painful ride as this client from EU went through, don't hire outsourced support service before you do at AT LEAST the following:
1. Speak to the company manager (voice is better) to get a good feeling of the company standards and communication approach.
2. Speak (voice and text) to the individual/s that the manager willing to assign on your project, demand reading their CVs as well before you making the voice call with them.
3. K.Y.E. (Know your employee), after you confident with the skill set, communication and approach of your potential team you are about to hire, only then - give them a test task / simulation and following their success you will give them the initial GO.
Some may say "too much hassle, too much time...I want hire quick...I need them ASAP" well - remember, if you will hire people you don't trust and dont know for even a bit, those people may cause to you much more hassle later during a real project of a real customer of yours and then you will have to spend much more time in getting the mess cleaned and looking for quality hires (again).
Hope my few tips would help you guys in finding the right outsourced team!