For a technical support scam, usually they will say "Hello, this is Microsoft Technical Support, how may I help you?" and then you reply with something like "Hello, I see a popup on my screen that tells me to call this number. It says I have a zeus virus and my computer is being hacked, can you help me?" (Atleast, that's how I have seen it on videos, as I don't have much experience myself) Also, now thinking of it, you could say "My computer is saying
that I have a zeus virus, can you help?" which would sound more realistic I would think.
I would recommend to watch some videos and see how they talk to people.
Also, it might just be your voice. 99.99% of younger people that call are scambaiters, and they know that. Some might even just hang up because they have had a bad day with lots of scambaiters and they think you're one even if you're convincing.
Then again, I don't have much personal experience, take my advice with a grain of salt.