Policies are completely unbinding on whoever they are intended for. They are ways a company or government decides to do things. For example, to enact a law, a government or company will implement certain policies in order to ensure their staff are ticking all the boxes and meeting their legal obligations. However, they are completely unbinding on you. You simply have to advise them that you do not consent to their policies.
A great example of this is that you can request to be removed from any automated systems and under GDPR they must obey this request, forcing them to go over and consider all your details manually.
Yet another great example is the name given to Garda (aka – police officers). Police officers are policy enforcers. They are not enforcing law, that would be practicing law without a licence. They are enforcing policies. These policies are based on laws written into a training manual and used to ensure the police tick all the boxes when arresting you, in order to ensure they have a strong case. Which is why you should never answer any questions, or cooperate with them unless it is under threat of force.
Removing yourself from policy obligations is simply a matter of advising the person in question that their internal policies are not binding on you, as you have signed no contract with them. You have the courage to stand there and refuse to allow the person serving you, to serve anyone else until they have settled the matter with you. If they refer you to a manager, for best effect, ensure the manage is also standing in a public area where you are delaying other customers from being served. You can go into a back room or somewhere to the side where customers can be served, but this only reduces the pressure on them to deal with the problem. That is your choice.