I received an annual invoice of €525,87 which I do not agree with because earlier in the year they advised me to lower my monthly payment installment due to under usage.When I started the contract in January of 2023 Engie advised me to set my monthly bill at around €194 which was fine for me.In June 2023 I got an email from Engie advising me to lower my monthly bill to just €10. Thinking it was a mistake I called the Engie helpline on June 28th 2023 and the customer representative confirmed that it was not a mistake and indeed I can lower it to €10 because I am underutilizing electricity and gas below expectations and will still get a refund when I receive my annual invoice in November 2023 because of overpaying for the first 7 months. Based on their advice I lowered my monthly bill to €30 still keeping it higher than what Engie had advised.In November and December, I called multiple times to inquire about when I will receive my annual invoice since it is due to me in November. They had no answer and kept on asking me to wait. On December 18th after waiting a month and half I finally received the annual invoice asking ME to pay €525,87.I have complained about this to Engie twice. First time when I called on 20th December 2023 I spoke with Manyck and he assured me they will look into it and let me know, I heard nothing afterwards. 2nd time I called on 28th December 2023 and spoke with Els, and she acknowledged all of this as being true but refused to do anything about it stating that my meter readings are the reason for this bill. But I ask, why did Engie advise me to lower my bill in the first place?I refuse to pay this bill because this is clearly a case of being mislead and fraudulent behavior from Engie. I expect compensation for this and am extremely disappointed by how Engie refuses to help despite acknowledging that what I am saying is all true.Best regards,Abdur Rafae ShahidClient Number: 2 209 681 112