Great Eastern Maxgrowth Endowment

10 years ago, I bought a Great Eastern MAXGROWTH endowment plan at OCBC. The sales person at OCBC says pay $10k for 5 years and upon maturity at 10th Year, you can get about 2+ % interest for the $50K. Just checked with the Great Eastern Customer Service, my maturity date is 21 Nov 2023 and the pay out is $55218.52. This is about 1% for 10 years, DAMN miserable. My question is Where can I seek Redress for this? I will have to wait till maturity to confirm how much I am getting though. I expect NOT much, just what the sales person promise me a 2+% will do.