I fill NEET 2020 form but when I paid fees it goes twice so total 3000 RS from my debit card transfer so how can I get that 1500 RS back ?

If you have paid the application fee for NEET twice, then they will refund you the excess amount which you have paid. Wait for 7 days you will get back the amount in the same bank account from where you paid the fee. If you don't get the refund then send a mail to the email mentioning your issue they will proceed your request, and send back the extra money you paid.