'No problem' is a problem

One of the big ah-ha moments in our customer service training sessions last week was the problem with 'no problem'.

Consider this scenario:

You:  Thank you for your payment, Mr. Smith.   You can expect a revised statement later this week.

Customer:  Thank you.

You:
1.  No problem.
2.  You're welcome.
3.  My pleasure.

Thoughts?

1.  'No problem' is a very common reply, and the problem is that this reply suggests there was a problem or that helping them was a problem.  

2.  This is nice and possibly expected. 

3.  Saying 'My pleasure' or 'Certainly' or "Happy to help' is the best option.  It is the most positive and service-orientated response.  

How many times do you say 'no problem' during your day?  Can you switch it up?