Declining advertising sales have been a big issue but my sales have dropped as well and that should not be happening.
This requires an in-depth analysis of your business, products, competitors, target market, revenue model, expenses/costs, sales model etc.
You can get general advice from anyone, but better advice from someone who is an expert (more specifically) in the product or services you provide.
Talk to an industry insider, to understand what's wrong in your company, and what needs to be improved, and whether it can be improved or not.