How can one get rid of repeatedly falling into successive sins and transgressions after repentance, and the feeling that God does not accept prayers, and the fear of His punishment, and not feeling the prayer, in order to return to God with a submissive heart?

The path of righteousness is clear and entails fulfilling obligations and abandoning prohibitions. What aids in this is pondering God’s names and attributes, remembering death and what comes after it, striving in supplication, keeping company with the righteous, and avoiding the causes of sin. One must earnestly and sincerely struggle against the self, recognize the danger and harm of sins, and not despair of repeated repentance after every sin until God grants success in sincere repentance.