Hi Buttermint,
Unfortunately, like other members of the forum that have been in similar circumstances, you are in a rather difficult situation when in effect you are forced to choose a mattress that won’t be particularly good quality or value and it may not be possible to even find out all the information you would need to make an informed choice.
The good news though is that post #2 here and some of the other posts and threads it links to can help you make the best of a difficult situation so you can make the best choice possible in your circumstances and give you some better options.
I would also make sure you have read post #1 here which is the basic tutorial post which covers all the basic information that will be the most helpful.
There are no easy or simple answers about what mattress to exchange for because everyone is unique but the information will help you with “how” to make the best possible choice.
The sleeping temperature of a mattress is affected by many factors not just the type of layers or materials in the mattress or the type of mattress. Post #2 here has more information that will be helpful.
When the time comes … the better options and possibilities I’m aware of in the Brookfield or Hermitage area (within 100 miles of Youngstown) are listed in post #2 here.
Phoenix