It sounds like you’ve set up a monthly subscription to Huel (which you would be able to cancel if you wanted!), rather than an actual purchase of Huel (or you have done both and the initial purchase confirmation email hasn’t sent - see First order confusion for someone else who recently did the same). There’s no reason why a simple delivery of Huel would take 27 days.
Best to email Huel’s customer service team@huel.com or call them 01296 678516 - or maybe @Tim_Huel can help.