You have now received guidance on what sort of phone is needed.
To that I would like to add that there lots of very nice GSM phones new and used, cheap to expensive to choose from. Some hang on pegs in orange Go Phone boxes alongside the one you bought. Used ones abound and most modern T-mobile phones are fine if unlocked. You can even buy direct from manufacturer stores. Go phone online store sometimes has outstanding deals. Currently offered A437 isn't bad at all.