All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Muhammad and upon all of his family and companions.
There is no harm if the laundry owner conditioned that the clothes won’t be guaranteed after a specific period so long as:
First: There was an earlier agreement in this regard (between the customer and the laundry owner) before handling clothes to the laundry.
Second: The laundry owner wasn’t negligent in keeping customer’s clothes.
Third: The owner should is obliged to handle the clothes to the customer even if the agreement was over in case they were intact.
Furthermore, Al-Imam An-Nawawi said:”According to the Shafiee’s adopted opinion, if an asset or any worthy belonging .i.e. clothes being entrusted to a tailor for the purpose of dying or stitching; in this case, the tailor isn’t obliged to guarantee them from any other damages occurred without being a part of it.” [Minhaj At-Talibeen pp. 162].
Finally, it is worth mentioning that after the end of warranty period, the laundry’s owner isn’t permitted to have the clothes; rather, he is obliged to keep them as much as possible, but if he couldn’t find their actual owner then he is permitted to give them as a charity to the poor. And Allah knows best.