You already asked that and I already answered that question for you.
Just because God has the power to do anything doesn't mean he does.
There's no reason to think that saints in Heaven can hear prayers. A group of people can make up any theology...doesn't mean that's a reason to think it's true.
God is perfectly sufficient and able to handle all prayers. There's no record in the massive history recorded in the Bible of a saint on earth praying to anyone but God. There's a reason for that.
Yes, the reason is that no human being was in heaven until Jesus died, so no one asked them to pray for them in heaven in the Old Testament because they weren't there yet. The righteous dead were in the "bosom of Abraham", waiting for their Savior.
The Old Testament was written before Jesus was born. The New Testament does not list very many prayers, and you have to remember that most of the people mentioned in the New Testament were still alive when the "books" of the New Testament were finished being written, so they would obviously not have been petitioned in heaven to pray for anyone here on Earth if they were still alive here on Earth themselves.
Goodnight.