In the Name of Allah, Most Merciful & Compassionate
Walaikum assalam,
Return policies are permissible to stipulate in contracts, as they are from standard market practice (`urf), and do not violate Shariah principles. [Taqi Usmani, Dars Tirmizi and elsewhere]
Buying something that has a return policy with the intention of returning it would return to standard market practice (`urf and ta`amul) in terms of whether it is acceptable or not–though it would not seem to be from proper conduct.
And Allah alone gives success.
