See section 2 of https://wiki.haskell.org/Taking_over_a_package

With the public e-mail+CC in place you can then either email the hackage admins after two weeks or immediately open a ticket on https://github.com/haskell-infra/hackage-trustees/issues , assuming no response from the maintainer admins can either give you maintainership (that you can give to someone else if you'd like), or they can do a non-maintainer upload with the fixes.

Cheers,

Adam