exten => s,1,Answer
exten => s,2,Set(TRIES=0)
exten => s,3(playback),Background(AAgreeting)
exten => s,4,WaitExten(6)

exten => i,1,Goto(internal,523,1)
exten => i,2,Goto(internal,599,1))

exten => t,1,Playback(im-sorry)
exten => t,2,Set(TRIES=$[${TRIES} +1])
exten => t,3,GoToIf($[${TRIES} >3]?disconnect)
exten => t,4,GoTo(s,playback)
exten => t,n(disconnect),Hangup()