One thing to add is that a less than optimal speaker/amp pairing does not necessarily mean that either device is faulty or defective. Just that they are not the best match for each other electronically.
Given that, depending on how long you have owned the amp or speakers, the best one might expect from a dealer is perhaps some trade-in value towards an upgrade. That's fine. Live and learn! If it has not been too long, a good dealer might offer full trade value, but even that is not a guarantee.
So if you want to move forward, find out what your dealer can and will do for you, but consider other buying options as well, including buying used to help minimize the loss when you try something that may or may not work out, which is often the case when one has discriminating ears.
