Q. I don't have all the figures needed to complete the tax credits renewal form and I'm worried I'll lose my tax credits as the deadline is 31 July. The main problem is, my income is as a musician and I don't know what my total income is until I receive the royalty statements.

A. Don't panic. You are required to return the tax credits renewals form by 31 July, or renew by phone, but you can submit estimated figures for 2011/12. When your self-employed accounts are ready you can submit the final figures and your tax credits award will be adjusted as necessary. As long as you submit final figures by 31 January 2013 you should not lose your tax credits.

Last month the Tax Office wrote to me saying I would no longer receive tax credits, but I did nothing about it. Now my wife is expecting another baby so has reduced her working hours. Can I get my tax credits back?

A. You need to make a new tax credits claim as soon as possible, don't wait until the new baby arrives. Your reduced family income may mean that you qualify for working and child tax credits already, and if you don't, you will at least have submitted a protective claim for 2012/13. Under the new rules, from 6 April 2012 couples with children must work at least 24 hours per week between them, and one member of the couple must work at least 16 hours per week. There are exceptions if one person is disabled, incapacitated or a carer.