Hitachi Vantara — It's been more than 24 days, But still didn't receive the offer letter

Address:	411028, Cybercity, Magarpatta, Hadapsar, Pune, Maharashtra 411028
Website:	www.hitachivantara.com/en-in/home.html

Hitachi Vantara has conducted 2 technical interview rounds for the Pune location in June 2022. They have requested a set of documents to release the offer letter. I shared the documents on June 21. After that, they had taken HR round on 27 June 2022 in that they offered me CTC and tell joining date of 27 July but from that day I haven't received any written confirmation from Hitachi Vantara. Even the recruitment firm Tactica Business Solutions which served as a mediator during this process is not responding to emails and calls. I wonder why they collected documents if they were not willing to release the offer.