Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
```
to exercise the right to cancel , you must inform us ( nintendo of europe gmbh , herriotstrasse 4 , 60528 frankfurt am main , germany , fax number : +49 69 667747 95412 , telephone number : for the uk and ireland : +44 345 60 50 247 / for other eu countries and south africa : +49 69 667747 5412 , email : for the uk and ireland : customer-support@nintendo.co.uk / for other eu countries and south africa : eshopservice@nintendo.de ) of your decision to cancel this contract by a clear statement ( e.g. a letter sent by post , fax or email ) . 

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