"Grab" tells me something about the way you take the towels. It is a more abrupt, quick motion. I wonder if there is an Italian verb for that. http://dictionary.reverso.net/english-italian/grab
When I look up "get" in my trusty app dictionary, it gives thirty words that can be used. Perhaps "get" is more often translated by one of those. BUT "prendere" is one of those words that can be used for a multitude of things. Just because DUO does not accept an answer, does not mean it is necessarily wrong. It took a long time to figure that out. Consider DUO like an obstinate friend - but a friend, nonetheless.
Hand towels exist in English, but, rather than foot towels, we say bath towels for the bigger ones and bath sheets for the biggest ones. I wonder if Italian as other kinds of towels too? http://dictionary.reverso.net/english-italian/towels http://dictionary.reverso.net/italian-english/telo
That is quite the opposite.