I'm Dissatisfied with My 3.5-liter Mi Air Fryer

I've been making use of a Mi air fryer with a capacity of 3.5 liters. It has a major problem in which the bottom of cakes, pastries, and even the lower part of meals don't cook properly, which is extremely frustrating. This problem even affects the lower part of meals. I'd like to get my money back. I contacted customer service about this issue, but they haven't responded to my inquiry yet. I have full faith that Mi will deal with this issue in the appropriate manner and take the necessary actions. I am wholly discontent with the item, and I require a remedy for my situation. In the event that the problem cannot be fixed, a refund might be an option.