Depending on how long the audio is, converting from a compressed format such as mp3 to a non compressed format such as wav, it might be difficult to turn 90mb into 10mb. It would be easier the other way round. If it can be done, I will do it for the pice I have bid. I will start it tonight and I will have it ready in 24 hours or sooner.
I have a BA Hons degree in Sound Production.
If it can't be done, I will tell you before the 24 hours is up and I won't charge you anything.