TravelUp — Cancellation of flightairtickets

I have booked the flight from Amsterdam to New Delhi on 17-Sept-2020 but after 1 week (on 24-Sept) got a mail from TravelUp team that my departure flight from Amsterdam to Delhi is canceled and an alternative flight is offered to me. But after giving my consent to an alternative flight again on 22nd Oct. got another mail stating that my return flight from Delhi to Amsterdam is canceled. I called on their UK customer care number multiple times but with no success (the only thing that happened is my call is transferred from one execution to another). The irony is after holding for a long time they put me on hold and then disconnected my call. Till now there are more than 24 emails back and forth (17 from my side and the rest from there). The last response I got from TravelUp is on the 29th of Oct. and after that, there is no reply from their side. I have shown my flexibility and have opted for alternative flights. I have given my preferred dates for both departure and arrival. If being so flexible still, they are not able to book my flight then I will opt for a full refund as it is their fault and there should not deduct any charges like administration fee or something else. Booking reference number 2095493