If you have need to contact their support, you will also find that they have the customers interest at heart, not like some other companies that I could perhaps mention. Buying from this company, you have made a wise decision.
As Woolwell says, when an original component is not available, most system builders substitute it with another of similar/better spec & value. I think the quality Lian Li PSU meets at least one of these criteria, so it'll be OK. They should have let you know though, & this lack of communication can annoy more than the substitute!
Lian Li are actually much better known for their lovely all-aluminium PC cases than PSUs! G