Review Hard Uncomfortable Mattress

My husband and I bought a 10inch high density mattress about 5days ago and we are disappointed
Our new mattress is extremely hard and uncomfortable, we experience bodily pains since 5days of usage
Want to know if your outfit can change for us, even if it means toping up. We should have been advised and caution of the nature of the mattress and given options to chose from,reason being the distributor admitted people complain alot about that type,
So we should buy a topper
Because we ordered online, we didn't have the opportunity to feel it for ourselves in person, big regret though.
Our money shouldn't go waste, something should be done about it