Autofill has an unknown number.

[tohwh79]

I have a S24U and I had autofill turned on.
It is very useful and I do not wish to disable this function.
But recently, I have this unknown number filling up the telephone number field.
I cannot remember where I got this number and how I saved it and I cannot find it anywhere.
Does anyone knows how to get rid of it ?Thank you in advance!