Dr. Eck’, would you please define for us the word “mediator”?
The definition of "mediator" is Jesus Christ, our only Saviour, as Scripture tells us. Christ, the only propitiation for our sins. Christ, the only one who redeems the lost sheep. Christ, the only means of our salvation who reconciles our sins by taking on the punishment for them and paying for every one of them on the cross.
"And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance." -- Hebrews 9:15
A mediator of our salvation, according to God's word, is one who "by means of death" pays for the sins of those whom God has adopted as His sons.
That is not Mary. Mary benefits from the "one mediator" as do all those who are called by God to His eternal inheritance.
"For there is one God, and one mediator between God and men, the man Christ Jesus;" -- 1 Timothy 2:5
From this clear teaching in Scripture, the RCC strays so far and in such collusion with the devil that it has the audacity to say that a creature, Mary, is some kind of mediator between God and men.
Flee from idolatry and the fables and lies that take your mind off Christ and turn your thoughts back on to the creature.