Do you have a preferred brand? If so I would look to see what online retailer carries that brand/style/size. We used to prefer Prevail for DD, but it was only for wetness not messes so I don't know if there is a difference. Prevail is carried by most major retailers. There are other retailers who specialize in such products, and I know for those whose insurance covers it they must be ordered through specific channels. But if you aren't looking for your insurance to cover (and I don't know if Canadian insurance would), you can order from any major retailer who has the brand/style/size you need.
If you need to have insurance reimburse, maybe you could buy at home and ship it to the resort. Shipments of medical supplies should not incur a fee from the resort so be sure they know it's medical supplies when you pick up the package.