No need to create an entirely new account to switch MSPs. Your Messages for Business account registration can be modified to connect to any approved MSP. This is available in the Apple Business Register portal at https://register.apple.com/messages.

The bubble color indicates the channel you are using. The Messages app on Apple devices supports three different channels: SMS - Unencrypted carrier messaging, indicated by the green bubbles iMessage - Encrypted Apple user to Apple user communication, indicated by the blue bubbles Messages for Business - Encrypted Apple user to business communication, indicated by the gray bubbles (see https://register.apple.com/messages) So SMS (green) and Messages for Business (gray) can be used for Apple users to communicate with businesses. iMessage (blue) is not intended for this purpose, and commercial messages would be considered spam. You can get access to Messages for Business via one of the Apple Authorized Messaging Service Providers (MSPs). There's a list on Apple's page for that at the URL above. Just know that it's not really for texting. It's for more advanced interactive customer experiences, with rich objects customers can tap to make selections, instead of just typing. If you just want to send customers order updates, SMS is probably the way to go. Hope this helps.