Some data sources insist on including country codes to telephone number (notably Fundraise Up). They are presented with a + and are either one or two digits long. You can use Importacular to remove these country codes from your data source, so that they are not imported into RE.
You can do this on using a regular expression data transformation that looks for a particular Country code in your data source and only import the numbers the succeed it.
The transformation would look like this:
These regular expressions assume that the phone number in the data source includes the country code at the beginning of the phone number and has a space between the country code and the phone number (for example +1 555-444-333 or +44 7777 555 666).
If the country code is one digit long, use the expression (?<=^.{3})[0-9].* that will seek to import the number after the third character (the space) and is represented in the expression by {3}
If the country code is two digits long, use the expression (?<=^.{4})[0-9].* that will seek to import the number after the fourth character (the space) and is represented in the expression by {4}.