Zivame — Multiple orders placed after changing consumer phone number from existing zivame account

I received sms on 6th January on multiple orders placed from my zivame account. I have not used the app for a week. I saw that my personal phone number was changed and replaced by a completely unknown number. Following this multiple orders were placed, with the OTP going to the new number, I had no control over my account. Some of the orders placed are non-cancellable. I doubt involvement of employee because it is not possible to change an existing phone number. I lost close to 4000 Rs. The same number is again trying to change the settings. I want my refunds and wish to close my account for good.