It's a bad habit to rely on calling a hero overpowered as a crutch. You don't want this to end up like LoL do you, where a popular hero gets nerfed to oblivion because people collectively scream OP too much. Look at her winrate, it's pretty normal.
TA has always been like this. Dealing with her requires two steps at all times.
1. Invisibility detection. If you don't have this, you can't stop her. It's impossible. It's like trying to stop Riki without invis detection. If you don't have some way to get this before she gets fed like... I dunno... Pudge with 16 kills before 30 minutes. Then you're going to be dealing with something equal to Pudge with 16 kills even if you get invis detection. Hell, i think Pudge is worse, because he's tanky as hell. Getting invis detection when she's already fed might be too late, though you never know.
2. A method to remove refraction. This one is up to your imagination. Last resort of hitting her seems to work. She has paper HP underneath that, which is why she relies on her invisibility. It takes some practice and creativity, but it's not impossible. If you can kill Pudge with 16 kills at minute 30, you can kill a TA no problem.
Just cover those two bases and you're set. Also, you need to identify if you lost explicitly because it was TA or if you would have lost if it was because your own play was terrible and the TA could have been played by Pugna and you'd still have lost. Because in that case, no amount of explicit counters can help you.
Sven isn't bad either. He only seems scary because of his ult. That's it. He's absolutely useless except at running away without his ult. So if you have some way to stop him during God's Strength, preferably something that can break BKB, then you're set. Even his stun is kinda meh. This can mean baiting him into using it, using heroes like Enigma or Bane that can CC through BKB, etc. Use some creativity. One popular method is to bait Sven into stunning you, then watching him activate God's Strength and running in before you turn on Ghost Sceptre. Now he's completely boned. Also, Sven is relatively squishy for a strength hero and he normally gets mask of madness, so you do even more damage to him.
All that being said, it can be very tough to fight these guys and if you wait too long to counter them then you'll never be able to stop them. But that's how Dota is. In Dota, the carries can actually carry the day if you leave them to their own devices.