From ancient times, pepole visiting tirupati take a vow of tonsuring their hair if their wish gets fulfilled. What happens if a person doesn't fulfill this vow? He took a vow of tonsuring his hair if his wish gets granted.His wish gets granted but he dont want to tonsure his hair now.Will God punish him for this?
Lord Balaji never punishes anyone. If you look into the history of Tirumala you will be admired how the process of vow fulfillment came into effect at Tirumala . https://www.tirumala.org/TempleLegend.aspx