Why GBP 30 has not come to the Available Balance yet

I got a job. But I couldn't do the job. The job was 100 GBP. Then Buyer was requested to 70 GBP refund. and gave me GBP 30. Then GBP 30 added to my freelancer Escrow Balance in 30-4-2021.
But my question is, Why GBP 30 has not come to the Available Balance yet?
It was 30-4-2021 but now 19-5-2021. It's been the past 19 days.
I need answer, please help.