Domande di colloquio per Software Engineer Java Developer presso Fujitsu

I went through 2 round of technical and managerial round .Finally there will be hr round . All went well and after 2 days of hr round I was offered as well but on the same day I received a separate mail stating my application has been rejected. When I tried calling and mailing hr there was no response from them. Be aware even if you receive offer letter keep searching for other options and keep it as last option