Yes sure we can fix your buckle prong for you...
CHECK that the holes are big enough for the new prong!!!! and for that matter check the old holes!
If all of this doesn’t help replace the buckles
If putting a prong back on, get it in place and crimp it with pinchers.
Once crimped it needs to still move freely.
This may all be a bit exaggerated but you get the point, round is good, flat is bad as it will bind and come off again.
If you don’t have the old prong, try and find one that you can take off a similar buckle and transfer over.
If you can’t find one the right size, get one the right colour and thickness and cut it to length, you may have to file the sharp end so that it is safe.