@slater1mark,
Do not EVER call back such a number! You have now confirmed to the actual scammers (the ones who phoned you) what your phone number is, that you are scammable, and moreover that your name is xxxx, your details are xxxx, etc. - whatever information it is that you have confirmed with them.
This is one of many well-known scams.
At least you had the sense not to install an app on your phone, but by calling them back, you've already made yourself vulnerable. Think carefully about what information you might have given them, or confirmed for them.
In future, be aware of such phishing calls. Check your eBay inbox to see if there's a message; check the Help page on eBay for a real number on which to call eBay about identity theft; post on these boards to ask for help - but do not ever ever ever call back when you've received a scam call. I hope your details are largely safe, and you should read through this eBay Help page on Recognising phishing phone calls and emails to inform yourself of what to do and what not to do.
