Which type of cell phone can get GSM roaming service phone in Canada

I brought my cell phon using in Korea to Canada and am still using it here to receive text messgae. SMS text message is no problem to read but MMS is not available to read by non GSM roaming service. I just got notice I received MMS but coul not open it to read.

Is there anyone experienced it and know what is the best way to read it or type of cell you know? I-Phone is fine to get it?

Thank you for your information if you advise.

Steve