Hammer it back.
Use a BFH and perhaps a second BFH to back up and just hammer it back into place.
This is not a space ship or a BFD.
Look for cracks etc.
If you are worried about the future and cracks, clean the area well and
paint with a satin white enamel and after it has dried
paint over with a gloss black.
If there are cracks or movement the black
paint will break along with the steel and the white will help show the cracks while they are small.
Of course you can throw money at it. When I rebuilt my
Scamp frame I used a bulldog coupling like above and I can recommend it, but you don't need a 10,000 coupling.