Have you spoken directly to the DHgate customer support?
I had a problem like this before, but there customer support for me was suprisingly good, and I got my refund through paypal in under a week.
My advice when buying from a seller on Dhgate would be to ask lots of questions to the seller before you buy, to:
1. Test their response time.
2. Test their interest level.
3. One of the most important things, (to me) test their english.
Time and time again I get chinese sellers who can't speak any english trying to sell products overseas. Trust me, I get very frustrated, and you can avoid this by asking questions first.
Do all these things and the chance of having to return the item or get a refund is minute.