Colossae is a city in Asia Minor.
Col 1:1Paul, an apostle of Christ Jesus by the will of God, and Timothy our brother,Col 1:2To the saints and faithful brothers in Christ at Colossae: Grace to you and peace from God our Father.
According to Colossians chapter 2, it seems Paul had probably never visited the church in Colossae. This is likely why he used the phrase 'those who have not seen my face in the flesh'.
Col 2:1For I want you to know how great a struggle I have for you and for those at Laodicea and for all who have not seen me in the flesh,
Throughout Colossians chapter 2, it appears that various heretical claims had entered the church in Colossae in a mixed form.