9 mths for a refund

After my holiday being cancelled due to covid I was asked to complete paperwork... I was then told that a refund will take upto 3 mths.... after not getting the refund in 3 mths I followed up without a response 5 mths later and I am now told it will take another 3 to 6 mths .... how can it take 9mths to return funds that they have ....what about the interest that is now due to me