Agitators
If it is determined that the Vari-Flex is actually broken and cannot be fixed, there are several agitators that I could recommend, including just as Martin said, a Roto-Swirl.
Most belt-drive agitators will fit, except the early large capacity agitators for the tall post 1967-1973 ish machines. Though most will fit, some I would say are too big for the tub size, including the Penta-Vane and Penta-Swirl. Also note the Dual-Action requires a Standard Cap auger to fit, as the very common large cap auger is too tall.
The Roto-Swirl and Whirlpool's standard capacity Super Surgilator would be be best and easiest to locate, in fact I have seen some on eBay brand new, even recently. Try looking for part number 285062 for the Roto-Swirl and 363633 for the Surgilator.
I have a new, never used white Roto-swirl if we can't find another, I can look up what I have invested in it.
In some cases a new agitator cap will be needed, part number 285155 or 285156 depending on color.
Hopefully the old agitator won't put up too much fuss during removal.
Gordon