You need to find where they are coming in from and block the entrance. If it is mice and not rats the exclusion is very easy because mice are real strong and won't chew as agressive as rats.
You can use 1/4 inch wire mesh and expandable foam to block entrances. Keep up trapping methods after exclusion for a week or two to make sure all are gone.
If you don't exclude you will trap forever because the other mice smell the scent of the others and party is on. One friendly piece of advice is not to use any poison inside the house because they will die inside in a far off corner and sometimes inside of walls and voids. Poisons are only for outside. Don't listen to claims they will eat poison and then go outside to get water because it is not true, I do this for a living and go into many homes that tried this method and have to find the dead creature which just requires a good nose.
If you have tried with mice traps and decon, and all kinds of mice poisons, then you need to take a cat. It is the best solution. The cat can help you to get rid of all of the mice in your house and the cat can become your pet for a long time.
If you have tried mouse traps and poison, then the best advice for you is to call an exterminator. Find a professional who will come out to evaluate your situation for free, and then give you an estimate on what it would cost for them to exterminate the mice from your home. Also find out if they have a warranty. Meaning if they mice come back within a certain amount of time, they will guarantee their work and come back out to exterminate for free.