Did you consider SEO/ social media campaigns and other channels for advertising? What was your marketing budget once you launched? What about targeting specific neighborhoods and condo buildings to get that X amount of customers in the system, then you might have gotten those customers to continue using the service. Start small and build your user base strong.
Michal I have a startup that just received funding would love to talk with you about some details, maybe your insight could really help.
My email is Jordanhamilton1@gmail.com