Can you come back when you have the wording with you. What you have said sounds more like a statement of facts that an actual charge.
It is a separate offence to fail to provide a sample at the roadside but the police usually only charge the main drink drive offence, or a fail to supply at the police station, and leave the roadside relatively minor offence as you would be facing a disqualification anyway.
Each offence you are charged with will have wording like I quoted before with the date and location and the reading, or the fail to supply, followed by the Act and Section that applies to that offence.
Also where is this alleged offence, England/ Wales, Northern Ireland or Scotland?