I left company "A" on July 5th due to poor HR policy and poor salary. I joined company 'B' on July 12th without a relieving letter. Then, after one month, company 'A' provided a relieving letter on August 21 but mentioned my last working day as August 21, which I never checked. After 2 years, I got an opportunity in company 'C' where company 'C' is not accepting me due to an overlap in dates and citing dual employment. However, I did not receive any salary from company 'A' for the months of July or August. Despite this, company 'A' is not correcting my relieving letter to reflect July 5th as my leaving day. Please advise me on how to overcome this situation so that I could pursue the opportunity in company "C."