To pay back, click this link to pay back. 

Input the number you requested the loan with

Then select the type of loan (For example: migo, extracash , ferratum etc) then select  "to repay"

And follow the prompts to input your debit card details to process the payment

Also note that some lenders will automatically debit you at due date, but it is advisable that you make a payment on the due date.