That file extension is usually from Globe Ransomware. Check the anti-virus manufacturer sites - some of them have free decrypters. Don't try Symantec but the ones along the lines of the smaller ones like Kaspersky, Emsisoft or Avast. And only download from their site. And scan it after you download.
A lot of the decrypters sites are like the ones where they fix your PC issues, just more malware, ransomware, viruses.
And then do something about the server getting viruses and malware. They've been getting more obnoxious with encrypting data in databases, not just files. Or get some bitcoins.

Sue