Courts will encourage relationships with both parents. Courts will frown upon either parent discouraging a child from maintaining such a relationship.
In many states, children over a certain age, often 11-14 varying by state, can "pick" where they live. But that goes to who has PRIMARY responsibility for the child. It doesn't mean the child has the option of stopping seeing the other parent. It just means they spend more time in the household that has primary. And in almost every place, judges can intervene if they feel the choice is not in the child's best interests.
Her calling you and conveying that message is a form of alienation.
In a business like, unemotional letter, sent via two means, notify her that the child does not have a right to just decide to stop seeing you, and that she doesn't have a right to stop him from seeing you. Call it access denial. Do not go on & on & on...keep it short, sweet & business like. Also in the letter, insist she not communicate through the child or share the nature of this dispute with the child. Give her 5 days to agree to compensatory times for the times she has denied the access.
Next time you are to see the child, follow orders EXACTLY as they stipulate on pick-up. If it says 6pm, you show up at 6pm...if pickups are at her home, show up at her home.....call via a cell phone with call detail reporting when you approach...wait at least 30 minutes...while there knock on two neighbor's doors...call before you leave....get a time-dated receipt from a neighborhood business.
Repeat the letter you wrote above, only documenting this incident. Give her five days to give you comp time. Send via two means, this time one of which is certified mail.
Do for a total of three times, then sue. Including fees.
The board is the sum of all of your great posts...Help divorced men be great dads! Divorce help in a father friendly divorce forum....more tips on how to deal with your divorce at DadsDivorce.com