The reason you may have struggled to reach HMRC, is because some staff were on strike on 31 January.
As a result of the strike action, HMRC have agreed that penalties will not be charged for returns that were filed on 1stor 2ndof February. Furthermore, interest will also not arise on any payments in respect of income tax received on 1stor 2ndof February either.
Normal penalties and interest charges will apply to returns filed or payments made on 3rdFebruary onwards, and remember the penalty regime is much more severe this year.
If you are finding it difficult to manage your tax affairs, your local TaxAssist Accountant would be happy to take care of them on your behalf.