Your node would lost all stat (used space and bandwidth, payments information from satellites, the ability to check a correctness of the payment, etc.) and all unsent orders (they will not be paid).
The customer can download some pieces for free from your node.
The repair request will fail to find any piece on your node.
Since your node will not be aware about used space, it can accept more pieces than have a free space and will fail to add any record to the database. It almost will stuck in this state until customer hopefully delete their data or SNO will find a way to add more free space and correct the availability in the config.
That’s all what I aware about.
It’s not fatal, but very inconvenient.