One question that tells you what "not interested" really means, and what to say for each of the three answers you'll get.

"Not interested" is rarely a real no. Most of the time the prospect is telling you one of three things: they don't see a problem, they don't think you can help, or they don't have time right now. Ask one question to find out which, then answer that, not the objection.
When a prospect says "not interested", don't argue and don't hang up. Ask:
"Got it. Just so I don't assume, are you saying [the problem you raised] isn't an issue for you, or have you tried other fixes and weren't happy with them?"
Their answer puts them into one of three groups, and each group needs a different response.
Prospects say it on reflex to get off the phone. It usually hides a more specific concern they haven't put into words yet. If you push harder, they dig in. If you ask what they mean, most will tell you, and then you have a real conversation.
What they're thinking: "We're doing fine."
What they may be missing: they think current results are good enough, or they're focused on a different problem and don't see how this one affects it.
What to say:
"Yeah, when I spoke to [similar companies], hitting [positive outcome] wasn't their top priority either, until they noticed [early warning signs] showing up more often. If that's not the case for you, what's your top focus right now?"
Why it works: you agree with them instead of challenging them, use similar companies as proof, raise warning signs they may have missed, and end on an open question that keeps them talking.
What they're thinking: "I've tried [other solutions] and they didn't work."
What they may be missing: they assume every option fails the same way. They may have been oversold before. They don't know how your approach is different.
What to say:
"Totally understand. Out of curiosity, what have you tried before to make [the problem] easier?"
Why it works: you respect their skepticism instead of triggering defensiveness. Their answer tells you exactly what went wrong last time, which is what your pitch needs to address.
What they're thinking: "I don't have time for this."
What they may be missing: they may be busy and still have the problem. They haven't connected what you do to their priorities, or they assume fixing it takes too much effort.
What to say:
"Totally fair, I know [their role] are slammed. Just so I know if it's worth calling back at a better time, would [positive outcome] be worth exploring?"
Why it works: it respects their time, asks a low-pressure question that's easy to say yes to, and leaves the door open for a better moment.
For the full call structure these responses fit into, see the cold call framework. If your SDRs need someone coaching them on calls every day, that's what our Fractional SDR Management does.