I have the encrypted files, the random IV for each encrypted files and the counter increment function but I miss the key. Is there anyway for me to decrypt the files?
No, there is no way.
The encrypted data and the IV are collectively called "the ciphertext", this is what is sent over the internet when you encrypt something. The details of the counter function (and the details of how AES works in general) are also public information. The only thing that's meant to be secret is the key, which you don't have.
In short, you have the cipher text but not the key. Unless you know of some secret military-level hack against AES, then you will not be able to recover the plaintext, ... that's the entire point of AES.