I agree with L.R.D. When we look for shoes we asked for the other one to try on and then when we buy the shoes we always ask for a fresh pair as one being out tried on all the time can make it larger, with lots of people with bigger feet can try the one shoe on.
Phil try on some shoes two weeks ago and one seemed a bit big. He asked the assistant for a fresh pair and she did not have his size, so, she ordered a pair to be sent to our house (no extra charge for postage). They arrived in two days and fitted perfectly, he also had 7 days to return them.
If you just got them, take them back and complain.
Alternatively do what Phil did a few days ago, go out and help with a horse and let it tread on your foot. That wil make it bigger. We can supply a horse if you wish.