Make sure you have consistent release rates and quality and send them an email at email@example.com. Or you can join the inkstone discord server and contact a content editor there. They will be able to provide you with a more detailed explanation.
You don't have to post it here. Did you get the message through inkstone? Then it's a legit contract.
And again, the minimum of 1,5k words daily is only to make you eligible for their MGS (Minimum Guarantee System - a system that gives new authors the assurance that they will be getting USD200/month for the first 4 months after their novel is going premium, regardless of their novel's earnings), which shouldn't be your goal to write in the first place anyway. If you decide to sign the contract and are later unable to upload 1,5k words daily for your premium chapters during the MGS period, there won't be a contract breach. It just means that you won't be able to get the USD200/month during the first 4 months after your novel goes premium. So, if the only thing that was keeping you from not signing the contract is the daily 1,5k words requirement, I'd tell you not to worry about it.