Have to admit, feeling slightly jaded with the game. Yet another week, still not got to silver 3. Was hit for 6 with defence battles. The limitations of 20 attack battles per day is setting you up to fail, Decided to give it a couple more weeks if no movement, it may be time to say goodnight to the game. If I was unable to beat the offence teams I would go "Ah well" and seek to improve my champs and equipment, as this isn't the case and I am failing because of defence battle, that I have little or no control over. Heres the rub if I get 20 off battles a day, then def battles should be equal or less than that.
What is your defense? If you are winning 90% on offense your defense must need some work. Have you tried leaving in defense entire week and fighting far up into green?
The refills are very cheap, if you can win as often as you state then a refill a day should provide a significant buffer even with a bad defense.