Fortunately we rarely deal with UK benefits or tax offices but when we do, oh wow the engaged phone! I had one elderly lady who used to live in the UK, came back to Jersey when she was widowed and that was the root of her problem. She was in receipt of a very small amount of income from the UK and the Inland Revenue (tax office) sent her tax returns each year, she didn't understand the late filing fee of £100 and assumed this was her tax bill so sent it to them each year. Finally she came to us, I contacted the tax people who wanted about six tax returns completed before they would refund this money. The problem really started when I tried to contact the UK department which paid her widows' pension to ask how much she had received each year so we could complete the forms, it took several weeks before I finally got answered, mostly the line was engaged. When I finally got through they told me they would give the information ONCE and only once, she had been notified at the time and they had better things to do. Sheesh! Yes, she got all her 'tax' refunded and the promise that they would never send her another tax form to complete as she doesn't earn enough to pay tax AND she is not liable to pay UK tax anyway as she isn't a resident of the UK.
Many a child has been spoiled because you can't spank a Grandma!