they should..your a U.S number calling a U.S number. unless you have another countries sim in i dont think youre restricted to calling any special way unless youre calling local places and numbers from there.

@syaoran 

I am just looking for a T Moble customer service number that I can call from Canada using a landline in Canada. I do not have a T moble phone or sim card...just a regular land line.  

T-Mobile can be reached from international numbers by callong: +1-505-998-3793.  Long distance charges will apply as that is obviously a long distance call from international locations. 

https://www.t-mobile.com/contact-us

same if theyre calling from a TMO phone while in Canada?

The call is free only if they are calling from their T-Mobile number.  Non-T-Mobile customers or T-Mobile customers not calling from their T-Mobile number will be charged long distance fees by whatever provider they are using.

ah missed the landline part lol.

I can call to the USA from  Canada for free on my landline.  However the international call center is in the Philippines and is long distance. I was hoping for a T-Mobile non 1-800 number based in the USA that I can call. 

unfortunately that would be a no..you can try contacting them through Facebook or Twitter as well..this will start you with tier 2 support over the call in tier 1 support agents.

Thanks for the help folks.  I had a TMO sim card card for use in USA that has expired.  Was hoping to call them to reactivate.  To do this on phone or app I need a current USA phone number …. mine has expired.   

I tried the TMO 1-800 number on my cell and it works….go figure.  Didn’t work on landline but does on cell!!