It's worth noting that a PCP isn't totally recoilless. Close but not totally. It's also worth noting that you can't take a PCP and put it on a rest indoors and expect every shooter to get the max accuracy from it. It still takes a lot of effort from the shooter to get the best out of the rifle.
Look at bench rest shooting or HFT.
I used a very vague guide of @ 18mm ( 5p ) edge to edge at 35 yards. If I got that everything was ok for me. If I didn't I was checking consistency of muzzle velocity ( I don't think that's been mentioned yet ), cleaning barrel, trying different pellet or pellet batches.
I've posted many times about the S10 from BSA that I bought. Through the mag I could get Bis Mags to group as above at 35 yards. No other pellet would get under an inch. I tried every popular pellet and various batches. I asked several AA FT shooters to try it for me. All said the rifle was hopeless with anything other than Bis Mags and it should go back.
BSA said it shot well with "A" pellet ... so use that pellet. I said I didn't want to use loopy 10+gr pellets in a sub 12fp rifle for HFT. BSA said I should have bought a target gun. Their gun is a hunting gun and it did shoot well with "A" pellet ... so use that pellet.
JB kindly tried to sort that rifle for me and fitted a new barrel and blueprinted the gun. Eventually we got it to a point where it was useable with Crosman Prems. Still very poor with AA/JSB and everything else ( apart from the originally good Bis Mags ). I also had a single shot adaptor made by Rancid Tom. That also tweaked in the groups with the Prems.
That seemed a reasonably common theme with 0.177 older BSA barrels. The more modern ones seem to be better now they are 'polished'. Maybe the answer for my old barrel was to 'polish' that barrel.
I've heard Chris C comment on a Steyr of his ( I think it was a Steyr ). He reluctantly polished it and it gave great accuracy.
So check the muzzle velocity consistency. I'd expect that to be under 20fps across a string of 20. Some talk of 3fps. Personally, I've not found 20fps makes that much difference. If you are getting above 20fps spread I'd start to think the delivery of the air to the pellet isn't right. You've probably got more chance of convincing the seller/manufacturer that it needs sorting by showing them chrono readings rather than shot groups.
If you aren't certain of your own ability then get a few other successful shooters give it a try. Again ... easier to say to a seller/manufacturer that several good shots have tried it.
If you aren't getting any joy regarding a replacement then maybe worth polishing the barrel ( if chrono readings are good ).