Many people were confused with the number changes, the taxes and everything related to landlines networks. The DVLA changed their number many times and people could not reach them properly. Take a look at this website where you can find the contact number for DVLA and call them at any time. They are avaliable for most of the day, thru the night also. But, be sure to visit the website and read more about what can you call them for. You can ask them for taxes. That is why I am asking you for more than a minute. Give them a shot and ask them what you need.
