What most bothers a Decision Maker is social and public pressure. You can get a person responsible for solving a petition to answer the supporters of the campaign. Encourage yourself to take sides for what matters to you. Take a look at these tactics online:
Easy online actions:
Share the petition on your social networks and ask your friends and family to also sign. Viralization is the key to make you listen.
Find the profile of the Decision Maker in social networks. Post on his/her wall and paste the link to the request.
Leave comments with the link of the petition on each photo, publication and tweet of the Decision Maker with the link of the petition and ask for an answer.
Ask your friends to also post on the wall of the Decision Maker.
Try to contact the Decision Maker privately, get his e-mail, talk to him by direct message or try to get his WhatsApp.