Flipkart — Samsung F41 /Flipkart upgrade plan

I have bought Mobile on Flipkart upgrade plan and after one year I have to pay due amount on 24 Oct 2020 but on app there is no payment option since then I am calling Flipkart for this issue everyone they said wait we've raised this issued etc etc. It's been more than 3 months my mobile is locked due to which I am not able to continue my work. Day before yesterday they sent me link over mail and SMS and I have paid the due amount but my mobile is still locked. I have called them they said to wait till 16th March. I mean this is very ridiculous. I could not appear for interviews as my application form is in this device. Now money Paid all done when will my mobile unlocked. I have to wait for 3 months more. This is very depressing. This is not expected from the company like Flipkart. Fake promises and fake resolutions.