Pseg overcharged and did not credit after the fact New Brunswick New Jersey

For more than 4 months now PSE&G has been ripping me off.I work out of town and am really never home.I spend a few hours in my apt on the weekend and my electric bill on the average for the previous years was always 20/30dollars.I know that things get more expensive but now my electric bills have been in the hundreds???.I still work out of town and spend even less time at my apt and my bills are in the hundreds???.so after takinging many days off to wait for one of there reps to come and investigate.they would sent a day and approx time and then never show??.So i have just contacted them again and after calling me a liar they finally and quickly adjusted my bill????back to 30 dollars???NO CREDIT for overpaying the previous 4 plus months HUNDREDS of dollars. What can i do to get my money back and stop them from taking advantage of me or any other person?????IF you are reading this and can offer advice ,i would appreciate it .

Morgan
jersey city, New Jersey
U.S.A.