Send Enquiry Question

Hi,

I have a single CPT(custom post type) with 2 pricing, one free, one paid with claim listing option enabled. The Send Enquiry/Send to Friend enabled.

What I want to do is, if a free listing is claimed, I don’t want the claimed person to edit the email until they upgrade to full paid listing.

So while in free listing, I want the inquiries to be sent to a default address and when paid, they can edit the email to whatever.

Currently from what I can understand is that I can enable “email” post field in the payment section and enable “send to friend”. Once the listing is claimed they can edit the email field.

Any way to adjust it so in the free listing, the email is sent but they cannot edit it once claimed unless paid?