Truncated Department Size from Contact Form

We have used the Sell API to connect a contact form from our website to our sell account and create a lead - without duplicating. The problem is that we have a field for "department size" and it's being truncated when the lead is generated and the "notes" field is filled in. Our options range from 0-9, 10-50, 51-100, etc... But only one number is coming through. Any ideas why??