You or another user in HubSpot does not see the phone number Group(s) containing your dedicated number(s) and instead see an option for a Default Group.

Follow the steps below to troubleshoot.

User's profile not added to the Group(s) in Sakari

Select the user's profile from the dropdown in the Users field in each Group to add them (see Create and manage Groups).

For more information, please see Configure a HubSpot user in Sakari.

Conversation exists in Unassigned Inbox in Sakari

Conversations started from a number that isn't dedicated to your account, or a number that wasn't yet added to a Group when the Conversation was started, reside in the Unassigned Inbox.

Conversations in the Unassigned Inbox aren't visible in HubSpot.  
 
Archive the Conversation in Sakari - then start a new one from the Contact record in HubSpot, selecting one of the existing Groups.