I have a 9 month year old bichonpoo and it still continually pees in the house? any ideas?

Sadie is her name and we take her out about 5-10 times a day, she will pee and poo outside but she will still go pee inside at any given moment, we have tried puppy pads, rubbed her nose in it, caught her in mid stream and gave her heck, sprayed the carpets so she doesn't smell her previous pee, tried crate training (peed in her crate and rolled in it), and just about everything else, we are currently trying the bell method and she will ring the bell when she wants to go outside, but still will pee in the house afterwards. It seems we havn't made the connection that we don't want her to pee in the house at all and not that we just perferr it if she went outside. Can anybody help, we are desperate. We have taking her to the vet since; we know it is uncommon for a 9month year old to pee so often and she has come crystals in her pee, we have changed her food 10 days ago so the food will break up the crystals and given her meds incase of a UTI, but the problem still remains. We need advice on how to get her to hold her pee longer and how to get her to warn us when she has to go pee so we can take her outside