For what do you need speed on your defense team? Literally just put 2 knight 2 healer, or 2 knight, healer, damage threat, or just 4 healers/revive, and nobody will even bother to attack you

The moment you do even one battle your chances of getting attacked are going up. That you only got hit a handful of times should be considered a win. If you simply don't attack anyone, maybe only do revenge battles, you're less likely to be targeted. 

Your def doesn't matter. Folks will assume no matter what your Def team is that at Challenger it's either a bluff or that they can take it down. Even more so if they're actively trying to climb, as they'll want to test what they're capable of before getting to the harder opponents. After all, any team you put together is one that someone up in Champion or Legend could put together with just the same. 

Eskalion's suggestion works better in higher tiers because it's mostly known by then that anyone on your def is less likely to be a meme/lacking gear/etc. At Challenger, the reality that it might not be a legit threat is too apparent. And even if it is assumed legit, will be a comp they need to figure a way around to climb higher anyway. 

you don't want to go down..

& you also don't want to go up..

how do you plan on getting conquest points?

1. There is no defense team that can defend against any comp. You gotta lose to some comp.

2. Instead of defend successfully, build a team that nobody wants to play against in the first place.

Try this:

FCC (Elbris)

T.Surin (MLDB)

A.Ravi, Arby (both on counter set)

All at least 200 speed with substantial ER, you'll win surprisingly more than expected on defense. A real pain to cleave or control lol.

Consider yourself blessed to only get attacked 5X in a week. Last week I got attacked 115X, with 37.5% winrate. My team is FCC, LR Krau with Crown of Glory, T.Surin, Politis damage build. Works wonders. I don’t get cleaved much, and I mostly lose to weird bruiser teams with specific combos to counter my team.

I get wins because I surprise them with crown of glory artifact, and damage Politis. Basically, you want to add an element of surprise on your def team. And survivability. Team synergy is important too. Double barrier plus skill null works well with T.Surin.

Make them be afraid to attack you. Politis by herself scares off CR push teams.

How did my defense team win against this

FCC,Landy,F.Tene,SSB vs my defense with G.Purrgis,LR.Krau,A.Ras and Achates(8k heals)

All of them are using aoe that is pushing my team and reduces krau cd which is also on candlestick

But still,my team if perfect for landy to spam her s3