Trend Micro released a Ransomware File Decryptor for victims of earlier Cerber v1 infections but it does not work on Cerber v2/v3 encrypted files or the newer v4x/v5x variants which use 10 random characters with a random 4 character (i.e. .b71c) extension. Unfortunately that means, there is still no way to decrypt files by these variants without paying the ransom.
If the decryption tools are not working, your last options are to do data recovery which usually works.
Encrypted files, are almost impossible to recover,
no decryption key best option is reformat and start over or pay the $ and hope that they return you your files