Reducing phone calls from customers? We get way too many calls for product customization and new features.

Our SaaS product that targets the enterprise gets way too many phone calls from customers. We can't remove the phone number completely, since it results in some sales leads.

Here are some things we've tried:

1. Making the phone number less prominent.
2. Integrating with a help desk software (ZenDesk) to allow customers to post support tickets there.

But we still get several calls a week. There isn't a dedicated support staff (we can't afford it right now) so our business co-founder has to handle all the calls himself.

Now you might be thinking, "That's great since you're getting feedback from customers", but many of the feature requests are only specific for individual customers. And aren't beneficial for the entire user base.

Any suggestions?

Setup an automated recording with options/extensions for the type of things customers call about and redirect the "feature suggestions" to a voicemail (that promises for the right person to call back or directs them to an online form to submit a feature suggestion) and leads to the co-founder answering the phone. I believe with a service like Grasshopper you can manage this type of a setup. People are not likely to select "help with a new account or sales" because people don't want to talk to sales people unless they have to.