Grade complaints: Master's thesis
Presumably, your master's thesis was graded by academics other than your supervisor. Since your supervisor read it and checked it on multiple occasions and considered it excellent. In particular, your supervisor advised that your analysis is more than enough (as opposed to weak and insufficient, as remarked by your graders). (I don't understand what is meant by: that is definately his comments [since] he is the only one on faculty to specialise on this topic. Firstly, what comments? Secondly, non-specialists can evaluate your work.) 


  Whom and how do I address these issues?


It seems your supervisor is on your side. I suggest meeting with them and discussing your grade. Assuming your supervisor believes your grade is unfair, they may be willing to champion any appeal and guide you through the process.

Beyond your supervisor, you need to follow whatever appeals procedure your institute has in place. I strongly suggest seeking the advice and support of a friendly faculty member, preferably someone you know reasonably well and someone who either knows the procedure well or is well-connected enough to find someone who is.