On your listing form towards the bottom below Postage >> Simple Delivery is Preferences >> Your settings, click on the little pencil icon there on the right, on the pop up screen which appears at the bottom you will see where to tick for Returns Accepted. Then click on Done.
Preferences
Your settings
3 working days handling
Item location BN20 0DB (Nr Eastbourne, United Kingdom)Postcode not visible on listing
No returns accepted Unless item is not as described
I'm am using a laptop with Chrome , sorry I do not use the limited app or mobile browser, may well be in a different place there.
@jehei_6377