I've ran into these more and more lately. Typically they're 30+, educated, in a good job and live their life to the fullest.
Dream women, right? They know what they want and know their sh1t. But, they don't chase. Their game is tight. Very rarely they make an effort to contact, if ever.
But, they when you contact them they do go out with you, or offer alternative time. Sometimes even cancel their other trivial plans to make time. Then you have absolutely a great evening, good talks, hot sex and after you leave in the morning you simply won't hear from them again unless you contact. This can go on for weeks, even months.
What kind of strategy to follow here? Initiating contact isn't anywhere near 50-50, hell 90-10 at best. You can not freeze them out. You can go NC but it has no effect as they are familiar with the game and know what you're doing. When you crack and call them again to ask them out everything is as good as ever.