Worst idea I've ever seen on this forum. Mining contracts are worthless and every cloud mining business is a scam until proven otherwise (earning profit or even breaking even - not counting nicehash here).
CMX is solving this exact issue. You have liquid token. So - if you have even 1 satoshi mined - you can go and sell your token at reasonable price. Get your ROI from selling token. You don't need to wait until you mine 100% ROI.