Emergency tax is an additional 10% deduction on top of the standard 20% rate, meaning your total tax deduction is now 30%.
There are two reasons this may happen:
Firstly, you should contact the CIS Helpline, and find out if you're registered for CIS. If you're not, then ask to register.
Secondly, you should double check the information you provided your contractor and make sure the UTR number is correct.
Yes! You will get this back when you complete the tax return for that tax year. If you get emergency taxed in June, you will have to wait until the following April before you can reclaim that additional 10%. This can be a huge delay, so make sure that you're registered ASAP!