After a point, I found I could buy other drinks more cheaply from Restaurant Depot and filled the fridges with them, reducing my orders from Coke. They must have realized because the rep returned and asked me to only store drinks we bought through them in the fridges.
How is this situation any different? Are suppliers unable to offer you a discount in exchange for exclusivity?
They asked you not to put their competitors' stuff in 'their' fridge. They didn't say that you weren't allowed to buy competitors' stuff without their permission, or require you to inform them if competitors even _talked_ to you.
Like, whether Coca Cola should be allowed do that is another question, but it _is_ a very different thing, and certainly a far less aggressive thing.
For what it's worth, though, both the FTC and the EC have repeatedly investigated Coca Cola over various anti-trust issues, including around how they deal with distributors.
CocaCola corporation kindly asked you to put only CocaCola corporation products in a fridge produced and owned by CocaCola corporation.
They didn't ask you to stop selling competitor products, let them know when you buy competitor products and certainly didn't ask for the receipts and told you them they will try to price-match them, and only allow you to buy competitor products if and only if they can't price match, which effectively limits what you can buy and sell.
On top of that what CocaCola corporation did has no place in law terminology, but what Corning allegedly did has a place [0].
If Coca Cola had reached an exclusive deal with 90+% of all retailers it would probably be subject to investigation.
It's the same story for all these anti-trust cases. No single action is inherently prohibited, it's the abuse of a dominant position that makes it problematic.
Another way to put it: the EU wants a competitive market, not a "free" one. It won't be waiting for an invisible hand to somewhat magically balance things.