I am sorry if your friend did not receive all the information she needs.
Every customer is responsible to settle its invoices on time. There is always a possibility to contact us to find a solution https://bit.ly/2BctIfo
If the contract of your friend has been cancelled, the CHF 500.- deposit you mentioned is a security for us. This guarantee can be refunded after 12 months.
For further assistance, I invite your friend to contact our finance service at 0800 800 800.