I have the same problem. After contacting my ISP and doing some troubleshooting their hosting provider seems to be blacklisting a bit to many IP's. If I use the TOR browser, I can reach their website just fine. You could try that as well.
They are using Shopify, so probably they have no control over provider blocking anything, probably that has a lot more to do with Shopify attempting to block spam attacks to other sites of their network.
Anyway user side it is a really bad user experience.