Quote from: bigbird on 30 March 2016, 07:22:07 pm

Definitely an unregistered Sim card.. I had a potential client that had called me before he had been reported a missing person, the police traced my number and turned up on my door step 

They can trace unregistered sim cards.

Ok so I found an answer to your Q

https://community.giffgaff.com/t5/Help-Support/Sim-card-has-no-phone-number/td-p/346995

Dont be concerned about your personal CC details being used for topping up. If you scroll up and read the replies on here, you will see that you have nothing to worry about.

Welcome to GiffGaff!

Even though this is an old thread, I'm just posting here as I didn't want to start up a new thread on the same subject.

I ordered a sim card which has arrived. It doesn't come pre-registered with a new mobile number, as I've checked my phone settings and it's definitely not on there. I didn't want to register this in my real name just in my work name with my work email. As it's on Giffgaff, the only option seems to be that I activate the sim online, create a new account, which includes an initial top up of a minimum of ?10 (to properly activate the sim such that it can make and receive calls) and pay that by registering my card details which obviously defeats the purpose. I tried to purchase an O2 top up (same network) from an ATM but it required the phone number which I obviously don't have and is it the same procedure over the counter or can you just buy a top up voucher without giving a phone number? My question is do I have to register my payment card in order to set up this sim or have I missed something? Is it the same process with all PAYG sims now?
 
Do I order a sim from Giff gaff website hun, I'm a returner to the industy and used to have a non smart phone and concerned about clients seeing you on whats app on a smart phone and don't see why I shouldn't have my face on my whats app.  I just want an old fashioned phone and unregistered sim for now till I get on my feet.  I know a smartphone is so useful but I can't cope with 2 smartphones at present.  Tried and failed after a test run a few weeks ago 

Just thought I'd update this; I bought a top up voucher and attempted to load the credit on the phone online. It would NOT allow me to apply the credit without first providing a name and address (and there was no way it would allow me to bypass the name and address request). So I gave a false name and a friend's address (with her permission).

this was the reason why I started this topic because I personally dont know how easy it is to obtain someones real info via a telephone number only. 

Well in my case somebody would have to check up my number to find the network and then get a job working for Tesco Mobile, or at least find and become good friends with somebody who did. They would need to have access to customers personal details, and could then presumably find out my legal name, address, bank details and whatever by searching the records for my number.

But what would they then do with this information? Every possible course of action they could take is going to get them (or their friend) fired, prosecuted and probably both? Going to lengths like this just to wind up being charged with harassment (which would include contacting me and telling me that they have this information more than once) and more than likely winding up in the local paper doesn't seem like a very sensible use of anybody's time to me.

Exactly, in the UK a person would have to commit fraud to obtain this type of information, or put their job at risk.