I now got full refund as they promised.
I tried another host with better reputation, but very disappointed. I think I should give MochaHost a try, 1GB RAM package is very affordable. Other VPS charge a lot even for 512 MB ram.
512 MB ram can do NOTHING at all. MySql will take over 300MB ram even if it is idle. Apache can easily take another 200 MB even with only 2 or 3 pages of web site open.
Basically 500MB RAM is barely enough for small personal project.
I would recommend 2 GB RAM instead of 500 MB Ram. 2GB ram should support more than ten (still, 10 active users may bring your server down) heavy users online for big web sites.