Although plans to announced to bring funeral plans within the remit of the FCA were announced in June of last year, I can find nothing online to suggest that they've actually done so yet.
One funeral plan website was welcoming the development as something yet to come as recently as last month, so it seems unlikely that the FCA currently formally regulates such plans. (Funeral plan companies have always been able to voluntarily register with the FCA, and agree to abide by their code of conduct, and that appears to still be the current position).
A better option might be to send a formal written demand to the company (using Royal Mail's 'Signed For' service), demanding your money and indicating that you will commence legal proceedings if you don't receive it within seven days.