I've followed the instructions for international long distance but it keeps telling me the number is not assigned. I receive calls from this number on my phone. I've copied and pasted the number (including country code 52) and added 011 and different variations including using the + sign but nothing works 
Hello Simon1234567,
Have you verified you're using the correct dialling format?
When dialling or texting international numbers, we must first include the International dialling prefix (IDP), followed by the Country calling code, followed by the phone number. The IDP is varies by country (see here). In Canada, the IDP is 011. Since the IDPs vary by country, the International dialling prefix can be replaced by the plus symbol, +.
So the proper international texting format is + followed by Country Calling Code followed by Area Code followed by phone number.
OR
011 followed by Country Calling Code followed by Area Code followed by phone number.
Does the phone number start with 01, 044 or 045 plus 10 digits? If yes, just dial the 10 digits. Are you trying to call a Mexican cellular phone? If so, you'll need to add the digit 1 between Country Calling Code (52 for Mexico) and the area code (see here).
Hope this helps 😀
Cheers
Hey @Tulipia
Welcome to the community 
To place a call to Mexico, you'd need to use the + sign (or 011), so it would look like this +52, then dial the phone number.
Are you able to place international long distance calls to other numbers?
Let us know!
