Dyson Is Yet To Refund The V15 Cordless Vacuum I Returned At The Door

I bought a V15 cordless vacuum cleaner through Dyson customer service. I returned it through the door and it's been 1 month, they still haven't deposited the money. They are stalling me that the process is ongoing. I called many times, they said 'we will call you' but they don't call. I didn't even bring the product into my house, I sent it back as soon as it arrived at the door. There is no cargo they are waiting for to make a return, there is no product that they need to look inside and examine whether it is intact or not, all of them went back to them as they sent them. The time that has passed is just their arbitrary waiting.