Credit Muga — I paid refund amount 1600. But he ask to me paid 3000

Dear Sir/Mam,
Yesterday i had a call from Credit Muga. They said me about loan and istall the app credit Muga but unfotunately i installed the app of credit muga but I have not applied for a loan of Rs 3000. But they creited the amount of rs 1600 with any agreement or deal in case i will not pay of Rs 3000. In Credit muga app show the amount of rs 3000 & even i will pay back of Rs 1600 instead 3000 Rs