Hi JS336,
Unfortunately your experience isn’t that uncommon because of some of the lower quality foams that are used in much of the iComfort lineup which are prone to softening much too quickly.
Hopefully your options include an actual refund rather than the much more common exchange policy which allows you to exchange for another mattress that they carry in the store at the same of higher cost.
If it is actually a refund … then you are fortunate and can “reboot” without much damage 
You have quite a better options in the general Columbus, OH area that I’m aware of and they are listed in post #2 here.
Phoenix