Hello

My mother (60 years old) recevied an Amex card few month ago (although not sure how, since she is unemployed and living on her pension checks), and made a purchase on the card, however she thought this was a credit card and in fact it was a charge card where the payment are due in full at the end of the month, she made a couple of monthly payment but this did not go well as she owed 650$ and couldnt keep up and the amex customer service did not like that either (monthly payment).

Now my mom moved out overseas, and I tried to explain this to the collectors but that did not go well either.
Now I received a letter from a Burns Vasan Associated, not sure if these are lawyers or another collection agency, in any case they are threatning of suing her and seizing any assets (not that she has any), or garnishing her wages.
My concerns is, can they garnish her pension? or sue her for this amount? especially when she is not here to defend herself? the letter came by mail and not by deliver.

Any feedback is greatly appreciated.

Thank you