Today's boxsprings are cheaply made and made to be rigid.
A platform bed provides similar support.
Since most of today's mattresses are upholstered with memory foam, my guess is that your problem is with the memory foam in your mattress.
Memory foam is a horrible product...specifically designed to cause the mattress to need frequent replacing.
For most of what is made today, equating expense with quality is a huge mistake.
And the truly diabolical part of memory foam is, that when you get off of the mattress, it looks perfectly fine, because the memory foam returns to its original shape.
The point being, that prevailing in a warranty claim is highly unlikely.
Memory foam has created a boon for the industry and a nightmare for the consumer.
There is no fix to this problem, other than to flip the mattress over and add a a soft latex topper to the underside.
This will put the memory foam at the bottom. The underside will provide firm support and the latex will give you the surface comfort you need to sleep well.
If possible, it would be best to get rid of that mattress and start over with a mattress that has no memory foam.
If going with "the fix", here is a link to the latex toppers. The EverEden all natural 2" Soft Talalay Latex Topper is all your need.
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