Postpe — RePayment link not working

Dear Sir I Had Used Postpe Credit Of Rs amount 5140 in Aug 2022. And Before I used It 3-4 times and Paid on Timely but This Time link Was Not opening At Payable time And Even after day by day It was not Open whenever I tried Screen got blanc even I had Got call from customer care and I had informed regarding. Now I had Paid My Dues Rs 5140/-. Now with late fee It became 6940/- approx . I got call also if you pay Pending Used amount Late fee will be Waived off but when I Paid They didn't do with Late fee anow I also Impact on my credit plz kindly resolve. I am already using other loans But Paid on Timely Even much more than Postpe.