Whats the best stats and cheapest gear for Tanking as Paladin?And where to farm?

So, I've got a char lv80 Blood Elf Protection Paladin and bought in the AH the most economic gear that I found at the auction house until I have reached 3.2k gs. Its my first time as a Tank, the other ones were a mage and a healer.

https://armory.warmane.com/character...ecrown/profile

I did 5 heroic dungeons, and in all of them my team was made of 5k+ gs and they were getting too much threat because of the imense amout of the damage they dealt, which sometimes I couldnt handle alone with Taunt and the paladin spell that redirects threat to me (idk the name of it now) plus Righteous Fury on. But it all went smooth since the mobs died fast. (and also they rushed and started the battle without me using consecration on ground to get all aggro)
However, in the last one, some of them were saying that I wasnt tanking properly (some reffering that I wasnt even a Tank), even though I was doing my rotations fine (in my opinion) following the 6969 method. And there was a comment about my shield (?), and I dont recall it well, but I believe it said "it was the first time a Tank got a shield"?

So with this context, I wanna know:

1. Whats the best status to focus as a protection paladin?
=>Because I dont know if I go to Threat or Survivability which is discussed in some guides. (Thats why in my set there is hit rating and expertise mixed with critical strike mixed with defense rating and block value)

2. Whats the best way to get the aggro back when I lost aggro to 3 party members?

3. What was the comment about Shield? I thought Prot Palading must wear shields, right?
=> (if its just the +36 Intellect, I can understand, it was the ONLY one that was selling in AH for an affordable price which was waaaay better than my last shield)

4. Where to farm high level Plate gear?

5. Whats the cheapest set of gear for a paladin prot tank?

6. Whats the best skill rotation to get aggro to me?

I am also accepting all tips that wasnt in these questions

Your gear is all over the place. Which in turn makes holding aggro harder, and survivability suffers from it as well.

1. Stats you want to focus on:
Defense Rating until you reach 540 Defense.
Stamina, hit & expertise, dodge/parry/block ratings.
Stamina is always good. You want hit & exp to be at reasonable levels to reliably keep aggro. Aim at 5% hit and 16 expertise for starters, or something like that. Work on them when you're more geared and preparing for actual raids and go for 8% hit & 26 expertise.
Pick whatever dodge/parry/block you get from gear along the way.

2. Seal of Command in AoE situations helps (it's from Retribution talent tree).
You have two taunts to use.
Hand of Salvation to reduce one's threat.
Tab targeting in AoE fights to distribute your aggro to prevent aggro loss.

3. Paladins do have few shield spells. Maybe they expected for you to use one of them. Sacred Shield maybe?

4. RDF N/HC for starters for you. After that it's ToC5, and Frozen Halls dungeons FoS, PoS, HoR. After those it's raids.

5. Go to AH, choose plate, start browsing. What's cheap, or worth it, comes down to person.
Whatever lower level dps/heal items you have, replace them. Even if it's with other similar level tank item, it will be much better for you.
Check Northrend reputation factions for gear upgrades too. Honored/Revered is fast to achieve with quests and occasional RDF with their tabard equipped.

Thanks for the answer!
If you dont mind, what Defense stats (540 Defense) we are talking about? The one that appears in Skill tab (in Character Info) alongside with all weapons skills and professions?
For me its locked at 400/400. It changes when I get more defense rating?

Wait, Ive just found haha, its not in the tab Skill, its actually in the Character Info
It just does not show at the Warmane Armory website haha
446 (400 + 46) with 230 def rating
Thank you again

the comment about "first time tank got a shield" is because your shield has intel on it. you need strength/stamina and other tank-benefiting stats (like + defense, +block, +dodge, etc). your current shield is not ideal for a pally tank.