I am working on a web portal where customers can manage how we contact them. It has been suggested that we could remove the postal option in order to save money, however I want to check this is permitted and whether it could be seen as exclusionary i.e. that we should offer marketing via all methods including post.
As you are a data controller, according to Article 4 GDPR – Definitions – you determine the purpose and means of the processing of personal data. I am supposing that you use consent as a legal ground or processing personal data in order to send marketing messages to the customers who accepted this. Article 4 GDPR – Definitions and Article 7 GDPR - Conditions for consent – request the consent to be “freely given, specific, informed and unambiguous” and presented “in an intelligible and easily accessible form, using clear and plain language”. That being said, you can choose what communication channels you offer to your customers – whether online or postal. So you can remove the postal option, just make sure that you collect the consent properly and you process the data respecting all GDPR requirements.