Fetching details from the dictionary...

I'm sorry to have kept you waiting
長い列に並んだ客に「お待ちどうさま」と言った。
I said 'thank you for waiting' to the customers in the long line.
予約のお客様に「お待ちどうさま」と声をかけた。
I said 'thank you for waiting' to the customer with a reservation.
お待ちどうさまでした、こちらがご注文の品です。
Sorry to keep you waiting, here is your order.