How to initiate a new email with an *existing* HME address
I have used hide-my-email to set up an account on a website. I need to *initiate* an email to their Helpdesk. How do I create an email with an *existing* relevant hme address I am using with a vendor? I don't want to create a new address which is the only option Mail offers. I want my email to come from the "User ID" email - my HME address - that is their reference for my membership. I cannot find any solution mentioned for a question people have asked for 3 years.
Is there any way to email anyone with an existing HME address or I can only reply if they email me? It makes this pretty useless for commerce if I cannot initiate contact with a website or merchant where they know my account by the HME address?