Snapmint Financial services private limited - Make a payment manually after that amount debited through autopay so emi paid twice

Make a may month payment manually on*st may on*th may again emi debited through autopay..writing and calling them from last ** days..with all the statements on **th June received mail in which they said to apply for chargeback in my bank but now bank deny from any help from their side they said I have to ask for refund I am frustrated from last * months because of Snapmint