petrifiedbutstanding
"The board did debate on it and were not pleased with it".
"The board debated over it and was not pleased with it".
the way in which you are rewriting the sentence is also correct, although it changes the meaning of the sentence
"The board did debate on it and was not pleased with it".this sentence is trying to say that "i assure you, the board did debate and was not pleased"
"The board debated over it and was not pleased with it".this sentence simply says that the board debated over the topic.
Do i make sense?
Yes that's the best way to explain it! The word did helps to give more weight/support to the argument.