The number you must have by default in the system is a mobile number (as it is SMS enabled).
This means that CALLS are by default from the mobile number.
Call rates from mobile numbers are more expensive, so many long inbound and outbound calls will add up.
To keep this cost down, we recommend calling OUT from the landline. To do this, ensure that you call from this button (found in the top right corner):
Then ensure you select the landline number from the dropdown at the bottom.
SMS was set up a long time ago. The architecture was not set up for emojis.
Without going into detail, sending emojis via SMS requires a different type of code architecture, and almost always uses more than 160 characters (the standard SMS length).
A few emojis can mean you send the equivalent of 3-4 'message segments'.
You get charged per segment, so keep them brief.