Wore much too quickly

We had a positive first impression of this mattress, and initially thought it was a great value. The mattress was very comfortable for the first three months that we had it. After this, however, we began to notice that the mattress was beginning to feel too soft. My husband is about thirty pounds heavier than me. This weight difference, which I do not think is significant, was enough to cause the mattress to compress significantly underneath him. The result was that I was laying on a downward slant, which resulted in significant discomfort and poor sleep. We are both of normal to below average size. We do not weigh enough to strain a mattress. Our mattress was positioned on a high quality platform bed, which is an appropriate foundation to rest this mattress on. After a few months, we were able to feel the many supporting bars of our foundation. The mattress was much too soft and unusable after just a few months. We had to replace this mattress after just eight months of use. The issues we had with this mattress were unfortunately not covered under the mattress warranty. In short, this mattress was garbage.