PIP

Hi all , am new to this site and like so many am struggling with the minefield of benefits , after six months I had a face to face assessment and today recieved a call to say "its bad news your claim has been unsuccessful" but we would like you to attend another assessment next month . When I asked why and questioned this I just got told that they want to do another assessment ! I am failing to see what more I can give them and what more can they assess and that having been through one crueling hour and half assessment why do I need another . I was told sometimes unfortunately they need too! But no answer given as to why ? Can anyone explain this to me ? Or has anyone else had to have two assessments done ?
Thanks for reading and hope someone can throw some light on this for me