I had an arm bend like that last year and had my local dealership replace it. I never knew what caused it, but I suspect the wind caught it and popped it. Too much force and it bent the arm. At the same time, the awning itself ripped on one corner where it's attached to the trailer.
But, mine was not warranty work. We'd owned the camper over 4 years when this happened. After the fact, I kicked myself because I probably could have claimed both the awning and the arm replacement on my insurance. But duh! Never thought of that and paid the price out of my own pocket.
You may have a hard time proving to the dealership it was already bent when you got home, but hold your guns and take it back and let them fix it at their expense. (that is, considering you did not do this).
FYI, I made the appointment with my local dealership, they evaluated the damage, set up an appointment when I should bring it in for the repair, and they ordered all the parts. The repair was set for about 2 weeks out. I took the camper in one evening, right after I got off work and before they closed. It was ready for pick up the next day before noon. I picked it back up after work and before they closed for the day.
To roll it back up, it's a 2 people process, maybe 3. One person to press the button to roll it up, and one person on each arm assisting the arms fold in place correct. Then, once rolled up, keep it that way and let the dealer unroll it and deal with it.
Good luck! Remember, if for some reason the dealership denies any responsibility and attempts to put it all on you, you still have insurance to fall back on so the cost is not ALL out of your own pocket.
And FYI, my dealership repaired mine with existing parts left over from another awning that bent the opposite arm. They only charged me for the cost of labor. Of course, I did have to buy a new awning too and pay the labor for the install. But the actual bend part of the arm, they gave me a freebee.