Everyone who posts on here about being limited always says that they had broken no rules. However Paypal do not ban you for 0 reason. What would be the point? They make far more money from you using your Paypal account than interest on any held money.
PayPal does review accounts regularly, and any concerns with security, violations of the User Agreement or Acceptable Use Agreement, compliance obligations, etc., could lead to a permanent restriction. Additional information beyond what would have been provided to you in a notification and/or email would not be available due also to security concerns and due to such information being proprietary....in other words they do not give you an exact reason, they just direct you to the user agreement or acceptable use policy. I guess having a reason wouldn't make any difference if they have permanently banned you.
If you have been told your Paypal account has been permanently limited then Paypal tends to hold any funds for 180 days. This is the same time frame that buyers have to open Paypal disputes.
If no disputes are opened in 180 days then normally you are allowed to withdraw the funds. That is as long as you are over 18, the account is in your legal name and registered in the country where you reside.