Booking refund

I had made a booking last year January to go in 27th March 2020 then lock down happened, I was told I can't get a refund I have to postpone, then I postpone to this year 26th march 2021 , they told me they forgot about my booking the place is booked, now I want a refund , they tell me they can't refund me. They can rather check for the next available date or another place. What can I do please help