Ferrothorn (F) @ Leftovers

Trait: Iron Barbs
EVs: 252 HP / 88 Def / 168 SDef
Impish Nature (+Def, -SAtk)
- Power Whip
- Leech Seed
- Thunder Wave
- Stealth Rock
Mamoswine (F) @ Choice Band

Trait: Thick Fat
EVs: 4 HP / 252 Atk / 252 Spd
Adamant Nature (+Atk, -SAtk)
- Icicle Crash
- Ice Shard
- Stone Edge
- Earthquake
Jolteon (M) @ Life Orb

Trait: Volt Absorb
EVs: 4 HP / 252 SAtk / 252 Spd
Modest Nature (+SAtk, -Atk)
- Agility
- Hidden Power [Ice]
- Shadow Ball
- Volt Switch
Gyarados (M) @ Life Orb

Trait: Moxie
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Dragon Dance
- Waterfall
- Ice Fang
- Earthquake
Gengar (M) @ Choice Scarf

Trait: Levitate
EVs: 4 HP / 252 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Hidden Power [Fire]
- Shadow Ball
- Focus Blast
- Giga Drain
Reuniclus (F) @ Life Orb

Trait: Magic Guard
EVs: 252 HP / 252 SAtk / 4 SDef
Modest Nature (+SAtk, -Atk)
- Calm Mind
- Focus Blast
- Psyshock
- Shadow Ball
Ive been losing a lot with this team and i need advice