Kiwi.com complaint: Kiwi had Changed the Air ticket dates automatically

On 26th June I booked a return ticket from UK to Sri Lanka. It was all sudden due to my grandmothers sudden demise. I am international student studying in UK and it was a lot of money around £1406. Even the decision was so hard to make I proceed ahead to give my final respect for my grandmother. We are so sure that we checked the dates me and my husband checked it plenty of time because the final day of funeral is 27th June. But after I paid the ticket dates had changed I tried contacting them but couldn’t and then I message them online but what they said Is I voluntarily cancelled my ticket. If I voluntarily cancelled it why should I place it from the first place? Before asking for a refund I tried to change the dates but it showed as booked but once me and my husband tried again for a new ticket it shows as its available within those dates I had selected before. I have no evidence to show that I choose the correct dates but finally its not just money I lost I couldn’t went for my grandmother’s funeral which cannot be turn back. I hope you all understand my situation so all I am asking is for a refund because its really hard for us to make a living here or else please give me dates the system had selected at least the money wont go in vain. Please refund my money thats all I am asking.