Yes, contact the seller first but
Do NOT allow the seller to promise a replacement.
It won't be any better and probably won't even arrive.
You want your money back.
If the seller does not give you a prompt refund (you may be asked to return the defective unit) go to the Resolution Centre at the bottom of this page and open an Item Not As Described dispute.
You will be told to return the unit to the seller. If the seller is in Canada you will get a return shipping label from the seller.
If the seller is in the USA she CANNOT send you a return shipping label and eBay does not understand this. You will have to trust that the seller will refund your return shipping but be ready not to get that cost back.
In either case use a tracked/Confirmed Delivery service to return the unit.
When the unit shows as delivered to the seller, you will be refunded your original cost and maybe your return shipping cost.
If your seller is in China, the unit is a fake*, the seller won't refund you, any replacement offered will never show up, and it is too expensive to return the unit with tracked shippiing which the seller will not refund.
Instead, while you should open the Not As Described Dispute to put your dissatisfaction on record, leave appropriate feedback for the seller. "Fake unit burned my hair and fell apart" would be reasonable.
At the same time you will be asked to leave Detailed Seller Ratings. The lowest Rating is ONE STAR. (A normal pleasant transaction gets Five Stars). No stars is a free pass.
If you get a refund through a Dispute, you cannot leave feedback.
*Which is why you have so many problems with it.
