Unfair Charge for Huawei Watch GT 3 Return

I bought the Huawei Watch GT 3 46 mm watch but was dissatisfied with it, therefore I requested a refund. The scenario, however, took an unexpected turn when they informed me that I couldn't return the watch since I had opened the box containing the complimentary earbuds that came with it. They also indicated that the earphones' cost will be subtracted from the watch's return. It seems unfair to me to be charged for an unused gift item that was delivered to me. This process has left me upset and disappointed, because I believe that returning a product should be painless and equitable. I don't understand the policy of removing the value of a gift item from a refund for a different product, and I hope Huawei reconsiders such practices in their return process.