Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
when you use the fitbit service after a modification becomes effective , you are telling us that you accept the modified terms . 

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