I want that my server works fine! Please help !

[Crapoutz]

I'm very very boring to have problems with my server.
All time I have error messages.
My server is dedicated server on VPS with 2.66GHz 4vcore Processor and 8Go Ram. Dedicatad server use 45% of processor and 40% of RAM.
I use this plugins : Backpacks, Christmas, CopyPaste, CountryBlock, DeathNotes, GUIAnnouncements, InfoPanel, NoDecay, NTeleportation, PreventLooting, RemoverTool, SignArtist, Skins, StackSizeController, TimeOfDay, TruePVE, ZLevelsRemastered and ZoneManager.
Errors messages :
- FlyHack: Enforcing (violation of 127.1194) + Kicked: FlyHack Violation Level 127.1194
- Dropped item container without inventory: item_drop_backpack[337704]
- ItemContainer.dropPosition dropped through
- ItemContainer.dropVelocity dropped through
- kicked: Steam: AuthTicketCanceled
- kicked: Packet Flooding: Player Tick
- MeleeHack: Entity too far away (axe_salvaged.entity on item_drop_backpack with 0.3419347m > 0.1m in 0.4121136s)
- CooldownHack: T-0.1640625s (hatchet.entity)
- AttackHack: Player stalled (m92.entity with 1.090837s)
- ProjectileHack: Missing ID (4)
I try to ask support, they answer one time and no more after.
Please, pleaseeeeeeeee help me !