Over a year ago I changed customers who were on the list for a very long time without buying anything to “unsubscribe” without realizing that I should have just created a segment to exclude them from getting a mailing. Instead I caused them to appear as if they opted out and are mixed in with those who actually unsubscribed. There were many and now I would like to send them an invite to come back (many have not actually unsubscribed). What is advisable to get them a message to check us out without violating spam laws? Would it be acceptable to subscribe everyone and then send an e-mail inviting them but with a clear way to re-unsubscribe if they want to.
No invitation is needed. If you can identify those customers, you can update their subscription status in the customer settings. Errors can happen, so it’s fine to correct them this way, but be careful not to send emails to customers who have unsubscribed or override their subscription preferences.
I don’t know what tool you’re using but can you sort out 2 segmentations: one is for those who really unsubscribed, and one for those you let them unsub by mistakes? If yes, then you can change their subscription yourself in the system. However, if no, you should really consider if it’s worth “inviting” them to opt in again because it will hurt your business when violating SPAM rules. A few sign up cannot outweigh the complaints and reputation damage. you can send a sequence asking for confirmation of preferences, if they click something like “I still want to receive email/I want to hear from you” then you can have them sign up again, and also immediately archive those who don’t engage with the campaign
Again, there’s a high chance this will hurt your business so consider carefully before making decision. You can always acquire new customers, retent current ones, rather than risking your business over lost ones.