call interview and by submitting my folio . after i submitted my folio i got a call from their end then my interview was conducted on call. and then i got a offer letter

It is really difficult getting through with the HR. When asking what is the update on the said postings that they said they would refer you to, they would ghost you when you tried reaching out to them which is very unprofessional. They should have at least informed that the post has been taken if one is inquiring about the update so they can move on.