pro tip: go on-location to a laptop shop, that happens to repair (even for warranty) etc
ringing and mailing usually isn't enough to bother, or gets 'pls pay 5-10€ for no reason'
source: worked at one, we had a full size box (1m x .5m x .5m) full of dead or half-dead keyboards, exactly for this purpose; most of them being lenovo (also lenovo has like 30 different kbds, keys are NOT interchangable)
if you're a respecting person, might as well give you one of the 50 i feel bad to say, but saying you're a past customer of them will almost gurantee a free key