I appreciate there is a documentation about Contact Definition and Count Determination in SFMC. There is also a reference for billing - the Contact Counts Report that can be created in Analytics Builder > Reports.
Having said that, I am still wondering how will my contacts in SFMC be charged considering:
- I have X contacts with Email Address only (they are used for email marketing)
- I will add Mobile Number for Y contacts (all these Y will be merged during the import with the X from the email channel and Y<X in my case)
Eventually, I will still have X individuals for the Email channel, but part of them (Y) will have also Mobile Number now.
Considering I will do that mobile numbers upload, will I be billed:
- for both X+Y immediately (even before sending to anyone in the mobile channel)
- for X contacts, but when I start to send to the mobile channel I will be billed for both X and those that were touched in the Mobile channel (at least once)
- still just for X (as the Y will be merged under the same Contact)