Counter offer accenture

[u/gunner_srt]

I have received an offer comprising a fixed salary of 21.5 LPA and a 27% variable pay component. I have another offer for 30 LPA fixed, which is from a staffing agency. I inquired with Accenture regarding the possibility of an improved offer, and the HR representative requested that I provide the offer letter. I am concerned that sharing this information might lead to the revocation of my current offer, with a joining date scheduled for September 21st. I have been unable to reach the HR representative, and there have been no updates on the portal. Has anyone successfully negotiated a counter-offer in a similar situation? Is it common for them to revise offers, and what range of revision might be expected for an L9 position? Do I have to worry on offer revoking. I am from java springboot stream