Are there any studies that prove/disprove the Oscillating Universe Theory?

The evidence suggests, strongly, that the expansion of the universe is accelerating. If an oscillating universe theory ruled that out then this would, in turn, dismiss this theory. As it is, it does strongly indicate that the idea that gravitational attraction would eventually slow the expansion of the universe and then send the expansion into reverse, is a false one.

But, you really need to be more specific in your question: which theory of an oscillating universe is it that you are asking about?