Thanks Jezz i did not know that .. apologies to white_feather for wrong advice ..
No problem, and you're not alone in that. Played a fourball betterball matchplay a few years ago, and one of our opponents tapped in a four-footer before I had a chance to say, "Oi, you can't do that?" Didn't bother making him replay it though as it was only a semi-friendly.
Repairing the hole is subject to one or two things too varied to explain here. Best to check the finer details of that one on www.randa.org where Decision 1-2/3.5 gives a fairly detailed answer