I have been to such sites recently in the lockdown in the way of earning online. But, honestly this is sheer waste of time, I feel. First of all, only few sites are legit that pay to read emails. The one you are talking of is probably Volutic as it's minimum payout is also the same. But, I tried it and attained that and when I applied for withdrawal here, it always showed balance error. One such site named Clickgennie also did the same issue with me, showing balance error. I also contact the support section, but they never replied.
However, I may be wrong. Please name the site that you are speaking of.