False advertising/ not true to size/ lack customer support

I purchased two pairs of the new 3.0 shoe. Shortly after that, they sent a generic email claiming that the sizing runs larger on this model, and that they have adjusted it to 'accommodate customers'. My size 6 was untrue to size and felt as if it was a size 8. I have never previously had issues when ordering shoes online with other retailers. I contacted them for a 'free exchange' as advertised on their homepage. However, they expect me to carry the cost of the payment for this exchange.

They have practice false advertising, don't care how they make their money, and do not seem to value their customers.

On further digging, their website has zero reviews on their review page. I wish I had seen that as a warning sign sooner. I am still trying to explain to them that this should not be a customers burden.