If a landlord ignores your landlord noise complaint letter without consent, you have several options to consider. First, document all communications and keep a record of the noise incidents. Next, you can try to follow up with your landlord, either in writing or by phone, to ensure they acknowledge your concerns. If the issue continues unresolved, you may explore legal options, such as contacting local housing authorities or consulting with a lawyer, to understand your rights and increase pressure on your landlord to address the problem.