I don't think the 2nd answer is good, for the reason that the other person has said. A modification of the first answer could be ok. Something like: I don't feel informed enough on the matter to have formed an opinion/to have come to any conclusions.

If someone says "I don't have a say", it means the person is powerless and has no control over the matter. Either way, the grammar might be correct, but the message amounts to professional suicide in a western company.

The first answer perfectly matches the reason that you gave: not knowing much about the matter. The second answer matches the following reasons: I don't have the right to say anything about this matter. I am not involved in this matter. I do not care about this matter. I don't care what happens regarding this matter. This matter is not important to me. As you can see, some of the reasons may be good and some may be bad, depending on the situation. None of them mean "I don't know much about this matter," though. So your first sentence is best.

U can say : i am not quite sure but as far as i know blah blah blah