Mfp for iOS?

I'm probably not posting this in the right place, but I'm having an issue with the link from my iphone (which tracks my steps) to mfp. I've been away from the site for a while, so I'm not sure if that has anything to do with it, but I can't even seem to find how I linked them in the first place! Its not life or death, obvs, but I'd like to be able to keep the data I track even across the board... Any help would be greatly appreciated!!!