Why is it so difficult to contact Yahoo! on matters of payment?

I paid for Yahoo! Mail Plus in February and now in March I am told that I have to pay again. I can find no direct way of trying to sort out this mess that they have caused. All I get is direction to Yahoo! answers. It is a most unprofessional way of dealing with things. I did eventually get linked up with a 'chat' service, but she was only responsible for dealing with technical matters, though she did give me a U.K. 'phone number. When the chat closed, I completed their survey, but it refused to accept it on account that I had not completed any of the questions (they all had a red asterisk), yet I had answered all of them! I 'phoned the number I was given and some man said he would deal with it and send me an email in an hour, that was yesterday and I am still waiting. I don't suppose anyone from Yahoo! will take the trouble to answer this question, customer service seems to be bottom of their list of priorities. I don't think I will bother with Mail Plus next year if this is the sort of problems it leads to.