Hotspot Shield is not able to refund

[Sergio____]

Hello, 
I bought a VPN service that does not work. I asked the seller to refund me but they can not process my requests for the problem below:

How can I ask them to fix the problem and refund me?
Their customer service tried to refund but it does not work. The Paypal system does not allow me to open a dispute for a refund. I bought a service for 2 years and it stopped working months ago. I had to buy another VPN service. How can I get my money back? Help please

 

Best,

Sergio