Complaints are an opportunity to improve.

As a founder, it can be easy to hear this advice and think, "I know, I know," but then go on doing the same things that customers consistently tell you they don't like or want. It's one of the biggest challenges of being a leader, to tell you the truth, because it means letting go of what you think is right-- and instead being open to the fact that you might be wrong, and that unhappy customers is the one who is right.

Entrepreneurs and businesses that live by this mentality are the ones that relentlessly improve. They care far more about delivering the best possible product or service to their customer than they do anything else--and as a path of achieving that goal, they work very hard to listen to the feedback their customers give them. And there is no better way of knowing whether you're improving than if customers keep coming back again and again. Retention is what great customer service looks like.

So, how can you take complaints as an opportunity to improve?

1. The expectations you have for yourself should be higher than the expectations the customer has for you.

If, at any point in the customer's experience, they are expecting more from you than you expect from yourself or your own company, then you know you have a problem that needs solving.

So many founders get caught up trying to "defend" their businesses that they forget to hear what it is the customer is actually trying to tell them. The customer is literally saying, "Here's what I expect," which means if you can meet that expectation, you'll have more happy customers. That's about as helpful as it gets--and far more helpful than any half-hearted business advice you'll get elsewhere.

2. Pay attention to whether or not your customer is unhappy because you broke a promise you made them.

Businesses that churn through customers left and right, I've found, are notorious for making promises they can't keep.

This almost always happens at the onset of the relationship. It doesn't matter whether it's a product or service-- all that matters is that a promise was made to the customer (whether it be a result, a benefit, or an ease of use), and that promise was not followed through on. The worst example here is when a customer was promised something by a specific date or time, and that time went and passed with no communication or apology.

When this happens, and you find yourself defending your company's "hard work and dedication to excellence," it's better to just scrap the PR speak and apologize. And then immediately after you apologize, you should meet with your team to figure out how to stop making promises you can't keep.

3. Keep track of how many customers become repeat buyers and/or refer you business.

Every business wants repeat customers.

The financial reason is because not only will these repeat customers refer other customers which lowers your customer acquisition cost, but it's much cheaper to keep a customer than it is to find a new one.

If a large part of your business is full of one-time buyers, you have a serious churn problem.

This is something I talk a lot about in my book, All In, and something I was exceedingly conscious of when I started my current business, LendingOne. Our company is focused on the professional real estate investor, and because that demographic is exceedingly expensive to target and acquire, our business thrives on repeat business--which is why we've spent so much time talking to our current customers, learning exactly what they need in order to feel great about doing business with us.

At the end of the day, a large part of building a successful company has everything to do with just doing what it is you say you're going to do. Customers hate feeling "duped," and they certainly don't enjoy voicing those frustrations only to be met with excuses. As a founder, you have to trust your customers are taking the time to share their frustrations with you because they want something you have the potential to give them. So, don't just sit there and defend yourself.

Listen and improve.