SIR – I am a self-employed consultant and my time is my income. I have the problem of holding two so-called unique taxpayer reference numbers with HMRC. As my tax has been assessed on one and paid on the other, I receive weekly messages from HMRC to pay my outstanding tax bill. Despite multiple phone calls, I still have not resolved the problem. Last Friday afternoon, I had yet another letter of demand and I tried, yet again, to call HMRC to explain, but now it says it is too busy to accept a ca