Consider the following movie clip a case study of how co-founders handle a customer service situation:
[Note: there are a couple of curse words in the above scene]
The job of an entrepreneur is to listen, and then to act on what’s heard
You know your product or service better than anyone else, but if a significant amount of your customers (or potential customers) clearly want something, you should work toward satisfying that demand. Even though co-founders Primo (Tony Shalhoub) and Secondo (Stanley Tucci) would have ideally liked to serve a customer in a different way, they made an informed decision based on what the market was telling them. (Sure, in this case it was just one customer, but you get the point.)
To sum up:
Get feedback (lots of it), especially from the kind of people that you envision using your product (and ideally paying for it). Then, make informed decisions based on what you learn. That’s how you build something truly valuable. If you try and breeze through customer development you will likely pay for it on the other side.