Travelstart refund not honoured

I had to receive a refund from Travelstart for a flight that was scheduled in March 2020. Every time I followed up they kept on informing me that it will take time due to Covid. I understand this and just kept on following up. They now informed me that they doubt that I will actually get my refund, as it has been so many months later. My travel insurance paid the difference between what I paid and what Travelstart said they would refund me. My travel insurance will not pay the portion that Travelstart said that they would pay that they are now going back on their word.