Seems as if you may be getting corruption on the connection. Does the library you are using support CRC? The RF chip does. If it is supported, enable it. I don't know anything about that library, but if it's any good it ought to enable you to configure the CRC checks, and also timeout and retransmission options. If so, the examples ought to demonstrate how to use these features. If you don't find that information, consider adopting ManiacBug's RF24 library instead - it is just as easy to use, works well, and comes with plenty of examples.