Why were two 0's added to the end of a String column?

Help
1

I have a column that stores many codes, I can run my bot until a certain point where I then receive this error:

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I understand it is because of the input string 9027809900 although in my Excel file this string does not exist. The column looks as so:

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I do not understand where the additional 0 characters are coming from and stopping my bot from running. Any ideas?

Thanks