Accenture India — Waiting for updated offer letter since 6 days. HR not responding. It is a location update.

I am Malavika, my CID is C9805914. I have received an offer letter from Accenture but the location mentioned in the offer letter is Bangalore and I was interviewed for Mumbai location. I had received the offer on 13th August 2021 at around 7.41pm. As soon as I saw the location as Bangalore I called up the HR and he said the location will be updated and it will take 4 days and I should not accept the offer till then. Then as they had mentioned in the offer letter that I would be getting a joining bonus if I joined before or on 18th Oct 2021 so I requested him to change the joining date too as 4 days means I will get the new offer on 17th August for that he said he will try to get the updated offer released on 16th August itself. I had a few questions so I emailed him those on 16th and did not get a response from him so called him on 17th and asked him about the updated offer but he had forgot what change had to be done. My deadline to accept the offer is on 20th August 2021. I am not sure if I will get the updated offer after experiencing such a response from him. Also he has mentioned nothing to me on email. He just talks on call and that to I have to call him and ask for updates and if he misses my call still he doesn’t give me a call back. I am ready to call him just that I am concerned that he should not forget to send me the updated offer letter. I emailed the HR on 18th August too but no response. Can you please help me with this. At least if I have in writing that the updated offer letter will be released to me then it would be great.
Hope to hear back from you.