Would you consider a vasectomy as a contraceptive method? Contraception is a method or device used to prevent pregnancy. People who are either married or not use this to stop pregnancy. There are those who are gifted by God to abstain from getting married and having children, and then there are others who are chemically or physically castrated to prevent the same. Those who have decided to live like eunuchs have a gift from God to abstain. The Apostle Paul considered himself to be gifted in being able to be single. Those who are married are also gifted for that purpose. The Holy Spirit could be considered a means of contraception to those who are gifted by God to stay single.
1Co 7:7 I wish that all of you were as I am. But each of you has your own gift from God; one has this gift, another has that.
1Co 7:8 Now to the unmarried and the widows I say: It is good for them to stay unmarried, as I do.
..... there are those who choose to live like eunuchs for the sake of the kingdom of heaven. The one who can accept this should accept it." Mark 19:12
I'll me try to answer each thing one at a time:
1) Vasectomies and tubal ligations are performed in order to restrict pregnancy while being able to have sex. It is a form of contraception.
2) Indeed, God has called for many to abstain from sex. But abstaining from sex is a different subject from contraception. Contraception is a means to have sex without the possibility of life being created.
There is nothing wrong with abstinence when it comes to those called to be abstinent. For those who aren't called to be abstinent, that means they are called to the vocation of marriage. And within that vocation, it means submitting to each other and both as one submitting their marriage to God.