Hello!
You mean reverse engineering right?
If you have the deobfuscated source code then this should be a relatively easy task. I have experience in writing c# and C++ applications and i did some reverse engineering work in my free time.
I think i could do it for around 400-500 USD but to be certain i need a look at the source code, i can go much lower than that.
I hope that you choose me, thanks!