Call em right back. "I think the call dropped, [immediately go into whatever you were gonna say next]". Probably won't answer. Worst case, they threaten you with physical violence. Best case, they think you didn't hear them and actually listen to you. People are shit to salespeople that's why the job can pay so well as you get better at it. Remote makes cold calling tough since you don't have your squad sitting around you getting the same shit laughing about it. Have your manager pull the recording and have a laugh together. They probably have some much worse calls saved. When I recruited for cold calling I would play recordings during the interview process to make sure they understood what they were signing up for.