Review Fraudulent act from Okash (Opay)

I paid #17,738 for repayment of my loan on 19 of July through app, Okash agent Disturbed me that my payment is not found that I should pay another money that my bank will reverce #17,738 back to my account, I paid another #18,858 on 24 of July. I got a mail from first bank that my payment of #17,738 was successful. I sent all the proof from bank to Okash agent but they ignore it