If you don't look after your customers, then your competitors will.
Apologies should include the words "sorry" and "apologise", and should be an apology for what you did, not for how people might have interpreted or misinterpreted your actions or felt about them. Anything else is called a "not-apology" and is only going to make things worse. Bonus points if your apology includes A) how you're going to compensate the people affected and B) how you're going to make sure that the bad thing doesn't happen in future.
If your customers emerge from their customer experience covered in blood, and that's entirely your fault, then you're doing something so wrong that it might be too late to give you any advice.