Hi jcarlucci88,
Sadly … your experience is not unusual and is part of the reason that I suggest that people avoid chain stores and major brands completely (see the guidelines here). As you unfortunately discovered … when you are considering a major brand or most mainstream mattresses … it’s certainly not the case that you will get what you pay for compared to the many better quality/value options that are available across the country.
Most mattress warranties are more about marketing than anything else and they have very little to do with the durability or useful life of a mattress (see post #174 here). Most major brand mattresses use lower quality and less durable materials in the comfort layers which can soften and compress or develop soft spots (or virtual impressions) much too quickly and result in the premature loss of comfort and support. Unfortunately the loss of comfort and support is not considered to be a manufacturing defect (which is the only thing that a mattress warranty covers) unless the visible impressions are deeper than the warranty exclusions. This is the reason that it’s so important to make sure you know the type and quality of all the materials inside any mattress you are considering (see this article) so you can make sure there are no weak links in the mattress (the quality guidelines I would suggest using are here) and which will also allow you to make more meaningful comparisons with other mattresses.
If you aren’t able to find out the information you need to make an informed purchase decision … I would pass the mattress by.
I would also be very cautious dealing with Bob’s Discount Furniture as well (see post #4 here) although your comments about dealing with local manufacturers is a very good idea and they will generally have much better quality and value mattresses in every budget range.
If you do decide to exchange your mattress for another one at Sleepy’s then post #2 here and the posts it links to may be useful to help you make the best of a difficult situation where you are stuck between a rock and a hard place.
If you decide to purchase a new mattress elsewhere then I would start with the tutorial post here which has all the basic information, steps, and guidelines you will need to make the best possible choices … and know how and why to avoid the worst ones.
Post #4 here also has some suggestions that may be helpful although there are no great solutions to “fix” a mattress that is sagging or has developed soft spots.
Phoenix