The past tense of Overpay is overpaid.
verb. ['ˈoʊvɝˌpeɪ'] pay too much.
1. Verb, base form It is always better to overpay than to underpay. 2. Verb, non-3rd person singular present You can get any amount you overpay refunded when you receive your next statement. 3. Noun, singular or mass You’ll either overpay or get scammed.