First, you don't need to worry at all. We are here to make your VPN work .You should immediately open your command prompt if on windows (go to Start > Run and type CMD press enter or if using MAC see here) and type this command.
telnet uk2.purevpn.net 1723
(For MAC you need hostname so it's uk2.purevpn.net and port number is 1723)
Press Enter and note the result If it gives a blank screen, this would mean PPTP is working on your ISP and you should check for:
1) Windows firewall blocking your connection (as it normally do) and allow VPN connection in rules
2) Anti-virus / Firewalls may be blocking connection. This most often happens when you have set your security level higher than normal.Then there is a second possibility that instead of a blank screen it says "cannot connect on port 1723 on uk2.purevpn.net", so we have another possibility.
Type this command: telnet uk2.purevpn.net 1701
If this one is working, means you should use L2TP protocol and you don't need to go for PPTP. If none helps submit a support ticket here
P.S : TELNET is not enabled by default in most OS so you will get "telnet is not recognized as internal or external command". If you see this, then you will need to enable TELNET as shown here