S2T Senior Software Engineer interview questions

only one round of interview and passed, then HR told me they are keen to hire me and asked my recent 3 months pay slips plus documents showing annual income so that they can offer me. but after I sent the documents, no progress and update for one week, so I asked how was it and the HR said they no longer want to hire me, very unprofessional and I think the bad rating about the company is true.