Am I being lied to?

I was told to talk to my account manager to see if I could be rehired into allied. I was never fired and had to do something else in order to take care of family (long story.)

Sorry, so I try to talk to the assistant manager, I've been waiting two weeks to redo onboarding. But I keep getting "it is harder to rehire someone than to bring a new person in."

Is that bs because I literally got a letter from hr saying I'm good terms and I could come back at anytime. Is this assistant acct manager being lazy/ incompetent, or are they telling the truth?