If the board is trying to retract, and actually does when you help it with your foot, then take some time to clean and lube the pivot points. This happens to me monthly during the winter. There are 4 pivot points on each running board. Use a can of WD40 and blast them liberally. A new, full can with the straw attached has good 'blasting' effect. Cycle the boards up and down a few times (may still need help retracting) then do it again. It's tough to get WD40 into the pin/sleeve but eventually it will work it's way in there. There's no easy way to lube these, and I would have liked to see grease zerts installed on these...bad design.
After you get them working again by using the WD40, I've tried various things like spray garage door lube, marine grease, and anything else I can find that's waterproof. Nothing lasts any longer than anything else because they just get blasted with road junk. Just using the WD40 every 30-60 days has made mine work great and reliably again, and it only takes a couple of minutes.
I would try this before buying anything new. Hope that helps.