What ticket system/Help Desk to choose?

The essence is this:
Need a customer support system.
Requirements:
1/ it should be ready-made solutions - the script, in order not to attract developers.
2/ the user must have the ability to create questions and looking at the history of answering tickets.

The point is to deliver a turnkey solution without prevline developers to integrate the system with existing service.
If you know something, I would be grateful)