In these days of instant communications one could be forgiven for coming to expect instant replies.
Unfortunately not everyone lives there life permanantly attached to the digital world, and have other, more pressing real world things to attend to. Whilst your frustration at waiting for a bespoke product to arrive within four days may be unacceptable to you, it might be more than reasonable to some to wait a bit longer for an item of a recommended quality.
Granted the vendor may well not have replied in as timely a fashion as you might come to expect, but that may possibly be because he's got your very item on the machine at the time.
A downside of this fast paced, instant, need it now world we seem to have developed is that people forget that some things still take the same time they always did. And some are worth the wait.
Personally, i have no experience of the seller you alude to (yet), but others here have and again are complimentary about the products themselves although granted, i don't recall much said about communications or the lack of.
Whilst the site may recommend this vendor and his wares, and indeed receive a contribution from the sales, i would suggest the admin of this site do an altogether better job of it than many, and venting ranted frustrations about what is essentially a non admin matter does nothing for the helpful and harmonious environment they appreciatively manage very well to maintain.