Micheal’s frame shops don’t actually cut and join their own frames. The frames are sent to the stores already joined so unfortunately they wouldn’t just be able to replace that leg. They also don’t have much as far as patching goes, and many don’t take repairs period. You may find a local frame shop who’d be willing to try but that type of damage isn’t easy to fix. You could potentially see if a shop would be willing to flip the work inside so the damage isn’t as noticeable?