I have had the misfortune of dealing with Etsilate for some years now, and they are the most difficult company to deal with especially when it comes to VoIP services.
I have to caution you in a very big way, in that YES there are a number of ways to bypass Etsilate and their blocking of VoIP packets, the way they do it is quite primitive really and is quite simple to get passed.
But… Here is where the problem exists, if you get caught you my friend are in a world of big problems, and i have seen too many people get thrown into Prison because of it, or fined heavily.
I had to work hard for 2 years with them to get a VoIP license in the UAE, and that license only works in the free trade zones, kind of pointless really but it was a start.
If you want to bypass their Blocking just change the part in which Etsilate are blocking, which is ports 5060 and also the ones that Skype use which i cant remember which ones they are, but there are about 6 of them.
Do not waste your time with a VPN, they have worked out ways to stop VoIP traffic over them, and that alone would get you into more trouble if they decided to hunt you down for that.
You should also try to use IAX2 where ever possible, they do not block it because of the Port it uses and also cause the VoIP packet overheads are not the same as SIP and H.323, their software on their routers are designed to sniff out SIP and H.323. However it wont be long before they start to block IAX2 as well.
What ever you do good luck, i hope nothing goes bad for you.