so when a message arrives from Telus that states welcome to Mexico they are referring to land only?
And that little sliver of water along the coast covered by terrestrial cellular towers. Once you are beyond 12 miles from shore, you are in international waters, and likely beyond any terrestrial cellular signals.
Unfortunately Roam at Sea isn't something that exists. Mexico, has easy roam but cruise ships are a whole separate thing. Telus has a page outlining cruise specific costs. It specifically states that roaming plans do not apply when on a cruise ship or airplane. The rates listed are more or less similar to what US carriers charge when dealing with cruise ships. Cruise ships use satellite and it's never cheap.
Easy Roam and Travel passes are not available for use on cruise ships or other satellite locations. Pay-per-use rates for cruise ships, in-flight and satellite locations are as follows:
Different rates apply to the countries where you port, and depend on whether you have Easy Roam, a travel pass, or continue using pay-per-use rates. Click here to find more information on roaming rates in a specific country.
As someone who has traveled a lot. Cruise ships must use satellites for internet and cellular connectivity though a micro cell tower built into the cruise ship. This makes use of any of those services incredibly expensive! The last cruise I took, it was $300 US for the unlimited internet package for the 7 days. Thankfully, T-Mobile WiFi Calling works everywhere, including on airplanes, which saved me a massive extra expense to keep in contact with friends and family.
When traveling, it is always on the user to know and understand the charges of using their cell phone abroad.
I think the OP fiance should contact TELUS again and see if they will give her a partial credit.
TELUS is under no obligation to provide any credits as the OP fiance made ano assumption that the TELUS roaming packages coveed cruise ships at sea. The TELUS website list what countries are covered by their roaming packages, and a cruise ship in international waters is not listed. Also they specifically state that cruise ships are not covered and warn about the high cost of the service.
The CRTC mandated caps on roaming fees do not apply to voice calls so TELUS is under no obligation to reduce these charges.