It's not that they never existed, it's that the genus is in review, and as yet the scientific community is not quite certain how to do the proper nomenclature.
One of the main researchers was eaten by a crocodile.
For a while the large spot Paratilapia was called bleekeri, and the small spot, polleni.
But what species was actually described and called polleni first in science, and which was dubbed bleekeri is the question (or were they both the same or not). Confusing enough?
Add to that there are at least 5 location variants that may at some point each be given species status.
If you weren't given a location, then it is very hard to determine what you may have.
below are a few of mine
Paratilapia sp. small spot male
Paratilapia sp "Andapa

and one I bought at a LFS, that can really be only considered
Paratilapia sp aquarium strain (no location given)

a reason for the aquarium strain name is, before it was realized there were more than 1 or 2 species they were indiscriminately mixed, and may have hybridized allowing for even more confusion.