You are well aware that the ESI ceiling limit is ₹15,000 per month on gross salary. If a person is drawing a salary not exceeding ₹15,000 per month, they will be covered under the ESI Act, and ESI contribution shall be payable on the gross salary at the applicable rate (Employee @ 1.75% & Employer @ 4.75%). In the ESI Act, there are two contribution periods, i.e., April to September & October to March.
Your salary was revised from June, and as such, you fall within the contribution period from March to September, due to which ESI contribution shall be deducted till September. Your HR Department will stop the deduction of ESI contribution from your salary with effect from October. However, it is to be noted that you will continue to get medical facilities from ESIC till the end of the next contribution period (October to March).