Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
all purchases of digital content are final , except as required by law or as described in our mobile and rift content refund policies . 

```
. OPTIONS: ['Jurisdiction' 'None' 'Arbitration' 'Unilateral termination'
 'Contract by using' 'Choice of law' 'Limitation of liability'
 'Unilateral change' 'Content removal'].