@QUEENDEE22, when going up against much stronger opponents try color stacking. Say your facing a green tank with blue flank (using this one for a specific reason) then you bring 3 red and 2 green hero’s. You can also go mono, all red, but at your level I wouldn’t necessarily recommend it.
You can also try the 2/2/1 set up where you have 2 of the color that is strong against the tank, 2 against the scariest flank and the 1 should be your healer of a color strong against the other flank.
When setting up defense it’s important to have your hero’s in a specific arrangement. You want the flank to be strong against the color the tank is weak against. I’ll add one of my favorite posts on Elemental damage.