Why the item you ordered does not exist yet, and why that is deliberate.
Print on demand means your item is manufactured after you place the order rather than pulled from stock. It adds two to four business days before shipping, and in exchange the item has never been stored, the colours match the current artwork file, and nothing is ever produced that nobody wanted.
It is slower than same-day dispatch, and it will always be slower — the item does not exist when you buy it. Personalised pieces cannot be resold, so they are not returnable unless flawed. And a rush order genuinely cannot skip production; there is no warehouse to raid.
The gap between order and dispatch is not a delay. It is the manufacturing.

Send a photo. If the fault is ours we remake and reship at no cost, and you do not need to post the original back. Unpersonalised items follow the standard 30-day policy; personalised ones are covered for faults but cannot be returned for a change of mind, because there is no second buyer for a mug with somebody's name on it.