Mine lasted two trips. We use a chip clip. Might as well stay true to the overall construction.
There are restringing kits available on Amazon and local RV dealers. And then when we restrung ours, we found the instructions on a random website (search: restring RV day night shades).
I personally would replace with a roller shade – can clean dust off, less bulk, better room darkening if that’s what you need.
There are probably a multitude of YouTube videos showing how to do this
There are blinds made now on Amazon that the string is built into the blind. They work great in my motorhome.
Replace it with something else. It will keep happening.
I took mine to a shade shop and had it restrung .