Help with income tax - someone help me please?

I used to have two jobs, I paid a normal rate of income tax on my main job, and then paid a higher rate on my second job. However, a few months ago, I left my main job and only kept my second job. Since then, I have been paying crazy amounts of tax coming out of my wages. This is my only job and I am only working part time and this is my only source of income. I have sent them my P45 and informed my employer several times, who has told me there is nothing they can do. I have also been unable to find any information on the internet. Can anyone tell me who I need to contact to claim my tax back, and more importantly how to stop them taking too much out of my next pay. Thanks

first phone or go to your local tax office and explain the situation,you could also contact citizens advice and or a reputable accountant,but talk to the inland revenue first and find out personally whats going on.

Ring your local tax office - info in telephone book -

Honestly go to your local tax office (even if it is distance) you should find them to be most help full That is what they are there for
The wicked tax man is a my the put out by accountants

Yes I agree, phone your tax office, you should have an employee tax reference number on your pay advice, you will need to give this info when you call, what will then happen is that the inland revenue will issue your employer with a paye coding notice (your tax code which will change from BR), then you should automatically get a rebate (if you are due one), when your deductions are calculated on the pay following the coding notification. Both your employer and yourself will receive the coding notice through the post at the same time, so you'll know when you should have it sorted, but this process can take a few weeks to sort out (especially coming into the christmas period), but once this is done everything will be sorted for you.

I'd ring straight through to Newcastle tax office which is the main one that all taxes go through but getting through to them on the phone can take ages.You need your NI number at the ready.
Ring up directories or the internet to get the number.

find out from your tax office why u must be on emergency tax and u will get it back eventualy i hope all the best i just paid 9000 拢 tax for a house i sold

A lot of what is in previous answers is speculation rather than facts. I'll try to explain to you. It is a bit difficult in that I don't know when you left your other job. My comments will assume this is after 6th April last. If it was before that date, your previous tax year will have to be reviewed with regard to a potential overpayment.
Your employer can't do anything. He is obliged by law to operate code number issued by HMRC. You said you sent P45 to them. Who are them? If you mean your employer, he can't use P45, as the leaving date on it is after the start of your employment with him. You still should have part 1a of that form P45.
It is no good contacting Newcastle. They only deal with National Insurance queries. Contact your employer's tax office, quoting his reference and your National Insurance number. Explain the situation to them. They may want to see your copy of P45/1a, or they may already have info. They will need to get rid of the sub-source record they have for your current job, and get your main record from your original job through. Explain that your second job is now your main job. This is where I go a bit hazy without all the facts. They may be able to calculate what allowance you have used at your previous job, and put a restriction in your current code number to cover this. If they can't do that, they may have to give you your personal allowance on a week 1 basis, which means that although from now on you will pay less tax, any repayment can't be calculated until the end of the tax year on 5th April. I'm afraid this is a disadvantage with the lower tax band 10% in force, as on your P45 there is no means of saying how much tax is at 10%, and how much at 22%
Should this scenario arise, after 6th April, as soon as you get form P60 from your employer, send that and form P45/1a to tax office, and claim your refund. Original forms only, photocopies not acceptable for repayment purposes.