Hi,
As the last two posts illustrate, 'feedback' is one of many words that is evolving, that is in a state of transition.
It's easy to sound awkward when using this word as a count noun. The previous post points out one way. Another example of awkwardness is to say something like 'Please look at this sentence and give me a feedback'.
My recommendation to learners is to treat it as uncountable when you use it. When you think you have a good understanding of how other people use the word, then you can start to be more ambitious.
Best wishes, Clive