RSVP

Id like to ask we are having a quincenera and we place a count at 200.we had some family and guest who were not promt with there RSVP so we called them and asked if they were going or not many of said they are coming. One relative we left a message and told them to get back to us
When they didnt return the call we went ahead counted our RSVP and paid for the dinners we get a call that they were not going to come because it was raining and now that it stopped they were, mind you this is a three days before the event, I eneded of calling them and letting them know that we were unable to accomadate them because they hadnt given us there RSVP in time. That we had already purchased the dinners I felt bad I have talked to many peoiple and they say I did the correct thing but what is actual ediquette.