The common "not interested" objection is a reflexive response, not a real reason. Instead of arguing, agree and offer multiple-choice reasons for their disinterest (e.g., problem isn't a priority, existing solution). This disarms them and surfaces the actual obstacle you need to address.
When a prospect claims to have no budget, agree and remove the pressure to buy now. Frame the meeting as an opportunity for them to get ahead. Explain that when budget does become available, those who have already done their research are first in line to receive it.
When a prospect says it's not their responsibility, don't ask for a direct referral, as they have no reason to advocate for you. Instead, ask for the much smaller favor of simply mentioning you spoke. This lower-stakes request is more likely to be granted and lets you control the narrative with the correct contact.
Don't call back immediately after being hung up on. Instead, wait a week, then call back and explicitly reference the date, time, and reason they gave before hanging up. Acknowledging they hung up on you shows preparation and humanity, disarming them and creating a better opportunity to state your case.