I had interviewed with a company and cleared all the rounds. HR called me and told and they will get back with an offer in a week, which they didn't.

I wrote a follow up email and then he told me that two teams are in talks for my candidature and now next day he is telling me that the team that interviewed me does not have vacancy as there has been an internal movement.

Now, the other team requires a Full stack developer and I work in Backend and also interviewed for the same.

I have waited for two weeks for this offer and now they are trying to reject me in this manner.

Please suggest what do I do in this case.