There was no New Testament for 40-60 years. The Church preceded scripture.
No the early church used the OT as it pointed to Christ as the fulfillment of the scriptures.. so there were scriptures and THOSE scriptures were being used daily in the church ... also scripture was being written as the admonitions and encouragements to the new church
2 Peter 3:15-16 - Meanwhile, consider that God's patience is meant to be man's salvation, as our dear brother Paul pointed out in his letter to you, written out of the wisdom God gave him. In that letter, as indeed in all his letters, he referred to these matters. There are, of course, some things in his letters which are difficult to understand (... it may help readers to know that even early Christian leaders had problems following some of Paul's teaching), and which unhappily, ill-informed and unbalanced people distort as they do other scriptures, and bring disaster on their own heads.