My dogs go to the toilet in the house, one is nearly 2 years old, i dont know what to do!?

i have 2 minuature dachshunds, they are my life, i live for them, suki is 1 and mr chips is nearly 2, they are both crate trained and wont go to the toilet in their crates but if i go out and leave them out of their crates they go to the toilet in the house! and at night, last night, during the night they did 3 poo's!! i fed them the night before, waited half hour, walked them, then walked them again before bed so it shouldnt have been a problem. i live in a flat, its not ideal but its a huge flat, and we go out to the garden pretty much every hour. but when i am out for 2 or 3 hours they go to the toilet in the house and i know they can hold it because they wouldnt do it if they were in the crate! Mr Chips had dominance issues when he was younger, where he would dirty if i closed a door in his face or left him, thats sorted now. they are definatly old enough to know better and i just dont know what to do. i hate the thought of leaving them in their crates when i am out all the time, its not fair, but neither is them pooing all over my floor when i know they can hold it!! any advice people i am open to all coments, views and advice, its really upsetting me now, what do i do? thank you xxx