I have returned a chair when they deliver to me in...

I have returned a chair when they deliver to me in some personal reason. I accept to be charged the shipping fee. However, it has past 50 days since I returned the chair, the refund hasn't arrived my account. Every time, when I call them, the customer service can only tell me the refund is in processing, no schedule, no deadline. Also tell me I will let you know if there is any update, well, to be honestly, I've never been noticed any update.
Terrible experience, never ever buy chair from this terrible company.