If you are in the USA, then what you received are unsolicited marketing phone calls under the TCPA, a law which allows you to personally collect up to $1500 per violation of the law or associated regulations, per phone call that you received. If your personal phone is on the federal "Do Not Call" registry, it's possible that there are at least two violations of the law per phone call you received. I would suggest sen…
I thought that companies you are doing business with are allowed to call you. He has an account, they can call. Also not a lawyer.
It sounds like his personal contact details are entirely separate from his business ones. I don't believe they should ever be using personal details to contact a business.
Even if he did provide them his phone number. In many places, that data may only be used for the purpose for which it was given. If they request a phone number for 2FA and then use it to contact you it could absolutely be considered illegal.