i don't think the problem is with pdproxy but with our service provider,
i have found another vpn server same as pdproxy and had issue's connecting.
i then mailed them and they replied :
A data sim with no data will not connect. We require an active internet connection to work. For mobile data connections which have a set limit, we cannot bypass this limit and give you free unlimited data. This is because your provider will still see how much data you use, with the VPN they will not know what sort of data you are using or where it's going or what you are doing with it, but they will still see you are using so much data. It is impossible to prevent this from happening.