Identify the unfair aspect with respect to the sentence extracted from an online Terms of Service:
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( b ) you may cancel our yearly , two year and forever subscription plans within the 30-day money back guarantee offer , which entitles you to cancel your subscription and have the full cost refunded to you up to 30 calendar days from your first date of payment , by emailing help@headspace.com . 

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