Did they fail the MOT and is there any excessive wobbling or vibrations in the car?
What I am getting at here is to get them checked at a second source. 3 buckled wheels seems really unlikely. I've only ever had a single buckled wheel in 15 years of driving.
Unfortunately it depends on the wheels and manufacturer. Back in the day, the MV2 wheels on E90's would be notorious from cracking due to runflats.
I used to think it's quite rare - until I managed to buy a set of 18" genuine Audi wheels last year 3 of which where buckled.
If it was noticed in an MOT - it should be quite visible. You can take the wheel car off and literally use a measuring tape to measure the inside diameter. Rotate around the "circle" and measure 10 times, there should be no deviation. Using this method I easily spotted the buckles on my Audi ones.
Alternatively any decent tyre shop can take the wheel off and put it on their balancing machine for a spin. Buckles are very easy to spot when the wheel is moving. If it rotates easily - you can spin the wheel on the car as well, without taking it off.
ebay is your friend, absolutely NOT going for the same price, here's a quick search, £500 for a set of 4:
https://www.ebay.co.uk/itm/Set-of-B...546309?hash=item4b50a520c5:g:Y~oAAOSwBCtbKBUf You'd be absolutely mad to buy new ones when eBay is full of OEM second hand ones for less than 1/4 a price.
While cracks can be mended/repaired and buckles as well - it tends to cost a fair whack and personally I don't like the idea of heating up a wheel and hammering it back into shape, I don't think the integrity is really the same. I'd go on eBay and get myself recond hand OEM replacements. You can avoid buckles with a measuring tape, as outlined above.