If you return both of them, according to Taobao's rules, whoever caused the return should pay the freight, so you should pay the freight twice, which is really a kind of backward payment. You can't let the seller return the freight for nothing, can you? The seller will go bankrupt. Remember, it's your return reason, not the seller's return reason.
One disadvantage of online shopping is that you can't see the real goods, so you can't take care of the buyer's feelings. When the buyer receives the goods, if he returns them due to dissatisfaction and other reasons (for example, the clothes are uncomfortable and the smell is bad and other garbage reasons, unfortunately, the landlord just wants to return them on this ground), the buyer should pay the freight.