Misleading Adidas Terrex Agravic Size

Hi

I bought the Adidas Terrex Agravic Speed on friday 26 July 2024 at the Menlyn Adidas shop. I have always been a loyal adidas customer when it comes to running shoes having bought almost all the Boston version, Super Novas etc. When buying my running shoe i have always been advised by Adidas consultants to buy one size up since i am an ultra runner, this logic has always worked up until the Terrex Agravic Speed. When i bought my shoe i was a bit uncomfortable with the fit of a UK 10 (my true size is UK9). I still bought the UK10 and this morning (31 July 2024) on my first run on the shoes, within the first 2-3km i felt that the shoes felt very lose and my ankle kept on moving up. I went back home and ended up running in my Boston 12's which are the same size UK10 but fit perfectly. I immediately took the shoes back to the shop as these will end up causing injuries if i carry on running in them. I explained my disappointment to the manager in that i felt the size of this shoe is misleading to the rest of the adidas running shoes i have worn in the past. The shoes are very expensive and i felt mislead. I requested to change the shoes for a 9.5 as i had seen online a lot of customers also complaining about the sizes. This request was rejected to my disappointment. As a loyal adidas customer i am seeking for assistance in this matter. Thank you