Inconsistent sizing frustration

Please could I get an explanation from someone at Pick 'n Pay with regards to the inconsistent clothing sizes. I am severely unhappy.

I bought a pair of the embroidered skinny jeans size 16 on Wednesday the 4th of May 2022, and these jeans fit me perfectly.

However, on Thursday the 5th of May 2022, the very next day, I bought a pair of boyfriend jeans also in a size 16, however these jeans are far too small!

Both jeans that I bought are the Real Denim Brand.

I do not understand how I can buy 2 pairs of jeans over 2 days, and have them be completely different sizes!! It makes zero sense.

I have another pair of straight leg Real Denim jeans that I bought last year, that are non-stretch, in a size 16, and these jeans still fit me perfectly. I have other pairs of Real Denim skinny jeans that are size 18 that are far too large for me, So I am confident that a size 16 is my size.

My concern is that these jeans are difficult to find (they are not even on the Pick 'n Pay Clothing store website) and that I will not be able to find another size, and will end up replacing them with another pair that I don't want, and I am so disappointed as I had been searching for months for a pair of these jeans in my size, and I was elated when I finally found one.

Please could I have an explanation.

Thank you.

Lauren Hofmaenner