Kiwi.com complaint: Refunded credit misapplication

Return Tickets for two people from Albany(Western Australia) to Adelaide ( Southern Australia) booked via Kiwi com. April 2020. Flights cancelled as result of COVID.
Kiwi.com booking number 108381427
Paid A$815.19.
Money not refunded but kept at Kiwi.com as Credit for future bookings.

Booked through Kiwi.com same return flight for May 2022.
Kiwi.com booking number 206036215
Cost : 913.85 Euros ( A$1332.26) – A$815.19 A$517
Total flying time 33hours plus.

Unfortunately believed that Kiwi.com would get me the best price.
Next day researched internet. Got best return flight for $772.
Total flying time : 8hr 30min.

Cancelled Kiwi.com booking .
Informed that the remaining credit with Kiwi.com was only A$ 15.

Kiwi.com gave no explanation.
A$800 was missing out of my Kiwi.com credit account.
Believe it was used as a cancellation fee.

Could Kiwi.com please refund the original A$815.19 to my new credit card account : Dr P J Claassen 4564 6800 2969 4212 Expiry : 1022

I am not planning to book another flight through Kiwi.com.

Thanking you in anticipation
Dr Petrus Claassen