Sounds like this shop don't know squonk.
You can use any bottom feeding rda with your dripbox - and there are more and more of them every day.
Maybe they were confused by the way that stock rda kind of "distributes" the juice with deck holes - but that's not how the juice GETS there - it gets there like EVERY bottom-feeder - through a hole in the pin.
So - YES get another bottom feed rda.
And since you mentioned Goon - MANY (not all) of the Goon clones (and the authentic Goon LP) COME WITH a bottom feed pin.
So you'd be all set.
So I've had a kangertech dripbox for quite some time and I've been wanting to change the RDA on it but I went to my local vape shop and said i couldn't due to my mod being a bottom feeder. I asked why and he said because the deck didn't the needed holes for the juices to flow up into the cotton. I should be fine to install a goon RDA or something of the sort as long as I don't use the squonk tank right?