You really don't give enough details for us to help, but I will try.
If your camera is exposed to external access, then it is quite normal for others to try and access it. As long as you have a string password and illegal login locks set then you can do little more. If you don't want anyone accessing your camera then use a VPN or lock down the source IP's to your mobile network etc. To reduce the was of anyone finding it see the end of this post.
If you think that they have accessed your Hikvision account then change the password or terminate using it.
Dont jump to conclusions that it is Russian hackers - It could well be an English/Indian/Norwegian user using Russia through a VPN, which would be pretty typical for those fishing for vulnerabilities using a VPN and spoofing their country.
If you have a router advertising port 80 for this camera then you can dramatically reduce the ease of anyone finding your camera by using port translation and using a high numbered random port.
You are also taking an enhanced level of risk by using http to access your camera remotely - You should be using https, else you will find your camera password quickly found via public wifi etc.