Have you thought about suggesting existing Customer Relationship Management (CRM) platforms? While they all have learning curves to tackle, they will still surely be time savers compared to starting from scratch.

I'm a big fan of Infusionsoft and a Certified Partner but if a robust solution like that is too big for your needs then there are others like Hubspot CRM or even Insightly.

They each manage contacts like a boss however they will each also have certain pros and cons that you'll want to research for your specific needs as well.