Does the practice of masturbation lead to prayers not being answered after repenting from it and then returning to it?

It is obligatory to repent from sin. Sins may be a reason for prayers not being answered, but that does not mean that Allah never answers the prayers of sinners, for no one is free from sin. Allah answered the prayer of Iblis, who is the worst of creatures. Therefore, strive in repentance and have a good opinion of Allah Almighty.