I sent an email a Japanese former colleage of mine, and he replied several weeks later. His reply included an emphatic apology for not replying sooner (返信が遅くなってしまって本当にごめんなさい。) Is there a polite phrase I can use in my reply to acknowledge his apology and let him know that I was not inconvenienced?
I am thinking 気にしないでください sounds inappropriately like forgiveness (when in fact the delay was understandable and not a problem).