Having price caps in place does not exclude a country or system to still be considered capitalist with rampant capitalism at work. While I agree that in general a free market capitalist society should let buyers/sellers solely determine prices, over time most developed nations have learned to practice a more nuanced form of capitalism because of the chaos that can ensue under unlimited price theory..
For example, most reasonable ppl are going to agree the United States and U.K. are pretty darn capitalist societies. So much so that historical enemies of these countries with different systems throw the 'capitalist pigs' label around quite frequently.
Yet in both the USA and UK, there are price cap regulations in place for utilities. In the USA, recently as 1984 price caps were put in place for telecom to limit the rates that could be charged, and in UK price caps on utilities like electricity, water, etc are common. This is a state power (e.g .Fdev) mandating a price cap (FC buy order price cap on tritium) - unless you don't consider the USA and UK reasonable examples of capitalism at work, you can't deny some regulations on capitalism is the norm.
So while I would concede the point that for any nation/system to be 100% capitalism, there would have to be zero regulations, I would also say this is a mythical unicorn and standard that does not exist in any real scenario - every modern country on earth that considers itself or is labelled by others as capitalist has some form of regulatory agencies throttling buyers/sellers (rent control, wage minimums in private sector, wage maximums for federal GS rated jobs, etc)