Couple of questions first
- do you know how he proposed charging? You write above about paying percentages, etc but is that what he offered? CFP does not actually defined how FINANCIAL advisor charges, that could be fee based (per hour), assets under management, or anything in between.
- do you know what services you and are not buying in what area those services are (accounting , financial advice, etc). You mention "advice" and that is a very loaded word
your CPA may not be unreasonable at all - think of it using legal advice as example
if you come to him for legal advice, the only real response he can give you (unless he is into business suicide) is I am not an attorney, please seek qualified advisor. now let us say, same CPA at great cost and investment gets licensed as a lawyer (JD, bar association ,etc.) and mentions this to you. you now have a choice of accepting or refusing such services, if you refuse and come to him for legal advice, his answer should be ' I am sorry, you are not my client for that service and I can not legally provide it to someone I do not have attorney-client relationship with'.
Same thing with financial/investment advice - it is highly regulated, monitored, and in a world people always attempt to blame others for the consequences of their decisions, very litigious. to provide financial advice, one needs to register with relevant authorities, disclose a lot of items up front and in course of engagement, collect and keep a lot of information to relevant authorities to request if/as needed should you ever raise a complaint or ask for arbitration or sue him.
If you do not want financial service and not entered into relevant engagement with him, he is absolutely right of being able to offer you any financial or investment advice. doing anything else is a direct violation of industry regulation, significant liability, and grounds for a lot of problems.
Now, with all of the above, in a free world, you are entitlement to change your providers at any time and for any reason
Similarly, he can fire you as a client for same perspective and probably should do so by referencing you to a different provider along with documentation transfer as a matter of courtesy. if he is now providing financial advice as part of consolidated practice and you clearly said you do not such advice from him, how soon it would be before two of you come to disagreement and you may think he is responding on an accounting matter and you later claim he provided you with investment/financial advice that you did not sign up for? "advice" - great, show us where client signed up for it? he didn't? oh, oh. problems all around, with FINRA, likely with your insurance , etc.
from a person who is not a CPA but works in financial services I would completely understand hesitance to respond to person who asks anything that may later be constituted as financial advice without having necessary engagement papers executed and myself covered. this is crazy thing to do.