Phone SIM Card Business

I want to use ERPNext for my business involving HP SIM cards and top-up vouchers.

There are only 2 products:

  • HP SIM cards
  • Top-up vouchers

HP SIM cards will have various phone numbers, for example:

  • 987473084
  • 625384944
  • 4787123128
  • etc.
    Differentiated using barcodes.

And the top-up vouchers will consist of:

  • SWA Operator, Rp 30,000
  • SWA Operator, Rp 100,000
  • etc.

How do I implement ERPNext with a use case like this?

Note:
We need to track the inventory, so I don’t think we can treat each number as 1 item record. Because if so, in the stock balance report, the stock will always remain at 1 unit.