I have come to the realization that customer service is one thing you cannot afford to be a loose end in your startup.Everyone knows the benefit of great customer service: you win over customers, secure future business, referrals and better LTV. Everyone knows this. Still we sometimes don't deliver. I am guilty of mistakes just like anyone else. With bad customer service: customers get angry because they feel powerless in a situation. They have invested time and/or money at this point. They are expecting you to deliver.A small percentage of the customers are truly plain PITA. They try to not pay, and/or complain a lot. Its easy for me to react badly over the phone. So, I prefer to do customer support over email. I try to get to the root cause rather than argue and keep the tone civil no matter what the provocation. (Much easier over email, also I can fix the tone, intent with the drafts). Moving on to the more common case, where the customer has a justified complaint or an issue she needs help with. I have realized that a timely response (not automated), telling the customer of the status is a great step one. (Automated response is fine if you have truly high email volume which is not scaling.) Even if the issue isn't resolved, if customers feel they are communicating with a human, the situation improves. Running a free service has this problem of the "browser" crowd using the service and expecting quality customer service. Servicing them is expensive as a startup and that's the real cost of freemium IMO. If you are able to up-sell very well, then this might be worth the trouble. Otherwise it might be a losing proposition. But still do this until it stops scaling. Your free customers will fix your processes, code bugs, etc etc. Finally, the KEY thing to realize is Customer acquisition is SUPER-expensive. Customer retention is what will really keep you profitable. So make sure you focus on customer retention A LOT. Referrals, LTV, everything. Make it your religion. We are doing it with ClearTax, here you can file your Income Tax Return online. Give us a whirl. :)