telGuarder is a website as well as an application for cell phones phones, which can tell you whether the unknown number that called you is a nuisance call or not.
If you accept annoying calls and you want to know who the caller is and what they want to tell you, then the most likely thing to do is simply search for their number on Google. There are websites such as White-pages that will reveal to you not only who he is but also his history.
telGuarder is such a website that speaks in addition to Greek and many languages and provides corresponding information for each country you declare to it. In his Greek version is a particularly useful tool as it displays all recent phone number ratings, along with user comments.
In addition to having a free app for Android and iOS, it can simply work from a browser. Simply go to their website, enter in the relevant field the number you want and see what other users write about this number.
You will also see various statistics, such as how many searches this number has had, how many references, what date the last search was, and a graphical table of fraud or safety rates.
Also an equally worthwhile app is truecaller and you can find it for free on the Play Store.
How I would like a machine. Unfulfilled dream.