AFAIK, lipstick doesn't exactly have an expiry date, though it will usually have a batch number indicating production date, and they can certainly go bad after a while or if not stored correctly.
I always start out by asking the customer to help me confirm the exact nature of their concerns so that I can provide the most appropriate resolution for the circumstances, which most often means photos indicating clearly what the problem is, and/or a more detailed description of the fault ("looks not nice" could be interpreted as a matter of personal opinion, which would in turn put it down to change of mind, but if it doesn't look nice because the lipstick has gone bad, it's a completely different matter).
Once I had those details, I would then decide on the best solution to offer. If the lipsticks are indeed spoiled, I would probably just suck it up and refund without return, as I couldn't do anything with them if I paid for the return, anyway. If nothing in their images or details indicates the lipsticks have spoiled, then I would be more inclined to offer refund of item price only, when received back in exactly the same condition as sent (I accept change of mind returns, though. If you don't, then you would not be under any obligation to accept them back).
I'd maybe try to negotiate a partial refund if some are still fine and they are happy to keep them.
