Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
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service contracts : the cancellation right expires earlier if the service has been fully performed by us , the performance of the service began with your prior express consent , and you acknowledged that you lose your right of cancellation once the contract has been fully performed . 

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