State law may provide a period of a year or less for returning an altered item, but check the language in your account agreement which will probably provide a much shorter time period in which the customer must draw it to your attention.
"Somewhat altered" is more than a little vague. You may get a little more accurate response with a little more information.
In this world you must be oh so smart or oh so pleasant. Well, for years I was smart. I recommend pleasant.