Calling from Teams Consumer / Skype consumer to Teams Account

Hi,

I'm looking for a solution to make a "free call" over the internet into Teams External number

Let me explain:

Employee1 has a Teams client with a call forward to his mobile phone.

Customer2 using Skype/Teams consumer

Customer2 is calling Employee1 -> call is dropping (in case Employee1 is doing "Simultaneously Ring" to his mobile. The call is reaching out to the Teams client perfectly but not on the cellular).

How can I give Skype/Teams consumer client or any other solution to call Teams Auto Attendant / a user that is doing forward to Auto Attendant?

Thanks in advance to all replyers