Greetings,
I can help you secure your website against DDoS attacks. It involves tuning certain kernel and firewall parameters. However, I cannot guarantee that this alone will do it, because there are many types of DDoS attacks. I have enough skill and experience, however to search for them and try to identify where the issue lies.
If you are interested, please send me a message and I will get back to you as soon as possible.
Until then, best regards.