Hi Meetjsh,
I dont understand how you will Use VPN for hacking other networks. Your Right, As you mentioned proxy servers usually track your IP in every 3 mins. So people can trace your IP.

Suggessions:
1. Use multiple Proxy. I mean use a proxy server, Log into another Proxy server, Log into another proxy.
2. Use certain application like proxy changer in which you can jump from diffrent proxy serverin every 3 mins.. before they can track your ip information