It's a scam.
Hi I have just signed up with you and I have brought my own number I used to do some tv and radio competitions now I don't know how I can stop any unwanted payments. I would like to do one ocasionally but don't want to have to start and stop. Can I do it when I please or am I opening a permenant door for them to keep sending me texes
Just received a text saying my account has been closed until I supply my details
Your giffgaff account has temporarily been locked, to avoid loss of connection confirm your details by checking here
*link removed* THIS IS A COPY OF THE TEXT MESSAGE PROBABLY A SCAM SO BEWARE
Were you in the UK when you received the call? While in the UK, all calls are free to receive unless it's a reverse charge call -- in which case the company operating the service must tell you the charges and ask if you accept the call. If you were not told the cost or did not accept the call, then it would be illegal for the operating company to charge you.
But why did you think it was a premium rate call? Did it give a caller ID beginning 084 or 09? There's still no charge for receiving the call -- you'll only be charged if you call the caller back, which is what the caller is hoping you will do.
But if you did receive a call with a caller ID starting 084 or 09, complain to ofcom. Doing that is possibly already illegal, but if it is not, then ofcom needs to change the law to prevent it fein happening.