Typically with ransomware, each victim's decrypter (decoder) provided by the malware developer is unique to them with their own private randomly generated RSA decryption key, password or personal ID which cannot be used with someone else's encrypted files. Sharing a decrypter, decryption key, password or personal ID provided by the cyber-criminals with another victim who paid the ransom will not work since the keys are different for each individual case. There are rare exceptions such as CryptoWall 3.0's decrypter where the criminals provided a unique KEY file, along with a standardized decrypt.exe file which decrypted based on that KEY file.
Further, there is no guarantee that the decrypter provided by the cyber-criminals will work properly and in some cases using an incorrect or faulty decrypter may cause additional damage or corruption of the already encrypted files.