That’s like when I got my shower sealed and then it started leaking within the warranty period. The company claimed that they were the new owners and had purchased the business but not the warranty obligations (!) and I’d have to find the original owner and try to make him honour the warranty. Which was complete BS, obviously, but it wasn’t worth taking to court. :/
There actually are legal ways to do that… instead of buying the company, you start a new company, and just buy assets of the old company (e.g. phone numbers, web sites, trademarks, customer lists). Seems shady but apparently it’s pretty common.