Wrongly Accused for Using Phone while Driving

I was followed by Garda while driving slowly looking for parking along on the roadside. They accused me for using a phone while driving. I was really shocked to hear this, as i was not even aware where my phone was, i had no intention at all to use the phone, i was infact looking for a parking lot! The lady said she saw me using a phone and i dropped t when i saw them. When she asked where my phone was, i pulled my two phones from the left pocket, the pocket was even strapped by the seat belt. I couldn't believe i was being charged for something i never did.

She insisted she saw me using the phone, and i had not used my phone at all, neither did i touch it. Infact my phones were beyond reach. To say the least though it may be said irrelevant, i had no call history on my two phones for the day.

garda says ,if i do not want to pay the fine (which is acknowledgement of guilty), i can wait for summons to court. Even in court, it may still be my word against Garda's word. I have no history of such fines or any road traffic fine to my name.

How can i be saved from this false accusation form garda?