Absolute best advice is if there is a problem with your serving team or food, speak with the head waiter for your section ASAP. This would apply to things like cold food, slow service, etc. They want you to be happy and will do what they can to fix the issue. If nothing changed after speaking to the head server, escalate it to the dining room manager or head of food and beverage. But they can't fix what they don't know about. And after the cruise it's too late for them to do anything about it.
Can it be a pain to take time out from your trip to discuss things? I suppose. But I'd think the time spent would be well worth it to not have those issues the whole cruise.