I implemented in-app billing into my app and am now testing its handling of refunds.
I bought my app\'s managed in-app billing item with a test account and refunded it.
I asked Google about this issue and they told me that it's not possible to re-buy an in-app billing item on Google Play if it was previously refunded. But when I tried to buy it again about 24 hours later, the purchase went through ...
So it looks like it's possible to re-buy, but only after some delay.