Taking down Emolga can be a pain in the butt, that's for sure, but there are a few strategies you can use to limit the damage that they cause, or use their blinding speed to your advantage.
The obvious best choice is Krokorok. Ground typing makes it immune to Volt Switch and Electro Ball, and Intimidate makes Pursuit/Quick Attack useless. Krokorok's biggest struggle is not being able to hit Emolga with Dig. To remedy this, in the past I have always taught my Krokorok the Rock Tomb TM, which can be found in the Relic Castle off of Route 4. Unlike Assurance or Crunch, Rock Tomb does not make contact, meaning that Emolga's Static will not screw you over. Should you get KOd by Acrobatics, the Speed debuffs should mean that your next Pokémon will outspeed Emolga. Krokorok eats Zebstrika for breakfast. Carry Paralyze Heals to shrug off Flaaffy's Static if it activates.
Boldore is another solid option. Sturdy means no cheese Electro Ball crits will KO, and helps patch up its paper-thin Special Defence. It learns two powerful Rock STABs by level 30, Rock Slide and Smack Down. Rock Slide is a powerful, and Smack Down lets you hit Emolga with Krokorok's Dig if needed. If possible, trade and evolve Boldore into Gigalith for maximum smackage.
Dwebble is a cuter alternative to Boldore. While it sacrifices a resistance to Zebstrika's Flame Charge, it gains Stealth Rock and Bug Bite to remove its Sitrus Berry. Smack Down, Rock Blast and Rock Slide can all be used to fight Emolga. It also has Sturdy. If you want to overlevel a bit, it evolves into the more resilient Crustle at level 34. It also gets Rock Polish is you want to reach ludicrous speed.
Vanillite is the worst option, but worth mentioning. It is slow and frail, and even a NeverMeltIce boosted Avalanche will likely not KO Emolga. But, it does get access to Icy Wind if you need to slow it down. It doesn't evolve until level 35, meaning unless you want to overlevel you will be stuck with a tiny ice cream cone. Keep away from Zebstrika or it will melt.