No, no matter what we do, we cannot pay even for one sin we committed much less all of them. You are really talking about two different things. We are saved when we believe in and receive Jesus Christ as our savior. God's grace is given to us through faith and NOT by any of our works or merit. He saved us, not because of righteous things we had done, but because of His mercy. (Titus 3:5) Repentance necessary for salvation is when we change our minds from following after dead works and come to Christ in faith.
Once we have been born again into God's family and indwelt by the Holy Spirit, if we (when we) commit sin, we may lose fellowship with our Heavenly Father - and that is because of our OWN shame and sense of not deserving God's love because we know in our hearts we have hurt Him - but we do not lose our salvation. We cannot because we are not saved by our own merit in the first place nor are we kept saved by our deserving it either. When we come to our senses and repent, confessing our sins to God in true humility and Godly sorrow, He is faithful and just to forgive us and He cleans us of all unrighteousness. Like Psalm 32:5 says, "Then I acknowledged my sin to you and did not cover up my iniquity. I said, "I will confess my transgressions to the LORD." And you forgave the guilt of my sin." That is a different matter than paying the debt of sin - which God says can ONLY be done by the shedding of blood.
If a believer dies before he/she has been brought to repentance over a sin (and there were some cases when God took people home before they could cause further damage to the cause of Christ), that believer would not have lost her/his salvation. God is constantly working in us to conform us into the image of Christ. He is merciful, he knows our frames and remembers we are but dust. As we mature and grow in our walk with the Lord, sin gradually loses its pull on us and we find that what we used to do and delight in doing we now look back in shame and remorse. Matthew Henry's Commentary says this about I John 1:9:
That is the matchless grace of our Creator. Praise His holy name!
“That is the matchless grace of our Creator. Praise His holy name!”
Yes indeed.