Ships & Modules

Battlecruiser, things like the Hurricane as excellent at both, speed to catch cruisers easily, as well as ab fit frigs, can decimate cruisers with its dps and cause frigates serious problems with double neuts/double webs + a flight of lights, excellent tracking on the guns further helps the cause.

I'd suggest a 1600mm plate fit with 220mms, double neuts, double webs, excellent for taking on multiple frigs/cruisers.

Vexor
Rupture
Arbitrator

All 3 can kill frigates witth drones+neut and are good vs cruisers

Vexor or Abitrator can send 5 bonused light drone after the frigs or 5 bonused medium drones after the cruisers. Tackle will always be a problem using a cruiser against a frig. Realistically you can't do it all in one ship. A Stabber might be another option. It has good speed for the tackle. Also the light missile spewing Caracal is another option against frigs.

Regardless, be prepared if you find success to no longer be one-on-one with the harrassers. They will either bait you into a group gank, or will stop engaging in their harrassment solo. You should be prepared as well to have buds to bait and group with. An excellent tech I cruiser to use as a wing mate is a Blackbird. As long as ecm is so powerful against tech I frigs and cruisers why not use it.

Have fun.

Edit - Ok why are you even talking about a Black Ops ship? From your op it sounded like you wanted a cheap solo option with which to fight in. Do you realize the sp and isk investment in a balck ops? And btw the BO ship is mostly just a bus for dropping other folks in bombers and recons on top of enemy ships. Rarely will you want it to engage in the fight as well.

Any cruiser with a medium neut will wreck a close range frig.

A Taranis Interceptor with a tracking disruptor will smash frigs and cruisers alike - but not 3v1.

A rupture with a 1600mm plate and neuts can sit on a station and gib people.

A Caracal with a full set of heavy missile (not rapid light) punches really hard.

but when it comes down to it, the best to beat them is to have friends show up and help out.

Navy Caracal is simply a frig terminator, has a decent tank and speed and if you fly it properly (requires good skills/fit) it's the tornado dude who's going to move on, those things have no tank and your Caracal is good enough to make it pee his pants/kill it (light missiles projection/dmg is better than many people think)

Navy Vexor is also a hell of a cruiser, properly tanked is very hard to hit (sign radius) provided you have top drone skills and tank. Of course this means you need to tackle the dam thing but even a noob in a simple celestis and damps/point can make that tornado look like an idiot.

♫
I have an arty Nado, I fly it every day,
When the frigs come hunting, I'll make the bastards pay.
Nado Nado Nado, it hits from 90k
Nado Nado Nado, I'll alpha them away.
♫

Frig/dessy/cruiser/BC. Either beat them at their own game, or take them out with ships designed to take out their ship classes.

If you're being harassed, harass them right back, with overwhelming force.

Your kid or future kids have the best freaking nursery rhymes .

Very generally speaking, destroyers will counter the frigates and battlecruisers will counter the cruisers.

Battleships counter battlecruisers, which counter cruisers, which counter destroyers, which counter frigates. Smaller ships (at close ranges) counter battleships provided you bring enough firepower and we're not talking about giant blobs (because giant blobs break the game's balancing due to the turret damage formula not modifying the sig res of turrets over range.)

AML Caracal, its cheap and effective, destroys Frigs and Dessys and can put a hurting on all but the tankiest Cruisers