The CAA has no legal powers to regulate tour operators' standards of service. You should first take up the complaint with the company concerned. If the matter remains unresolved and the company is a member of either ABTA, TTA or The Global Travel Group you should contact them for advice. If not, try Consumer Direct on 08454 040506.
If you have booked with an ATOL holder that has ceased trading see the Failed Companies pages to see if you can claim a refund.