Pobuca Connect offers 3 plans, Free, Pro and Enterprise and each one of them has different limits for the total number of contacts that you can store.
The Free version has 2 limitations: the first one is that the maximum number of contacts is 50,000. The second is a relation between number of users and contacts; the maximum number of 50,000 is offered if you have more than 10 users - for less than 10 users the limit is [number of users] x 5,000 contacts.
Let's see 2 examples for the free version:
If you have 5 users in your Pobuca Connect subscription, then you can have 5 users * 5,000 contacts = 25,000 contacts in total
If you have 12 users you can have 50,000 contacts in total since this the maximum for Free version.
With Pro version the case is the same, but the maximum number is 100,000 contacts (instead of 50,000) and each user brings 10,000 contacts (instead of 5,000)
The Enterprise version offers unlimited number of contacts and the only hard-limit comes from the capacity of your smartphones and the performance issues they may have (especially older models) if you sync more than 100,000 contacts.
PS. All Pobuca Connect versions (Free included) support unlimited number of users