The customer will refer to the fare he/she saw online.
These fares can be retrieved via this (internal) link.
United States (America): https://www.budgetair.com/en_us?ch=call2bookagentus
United Kingdom (England): https://www.budgetair.co.uk/?ch=call2bookagentuk
Canada: https://www.budgetair.com/en_ca?ch=call2bookagentca
Germany: www.cheaptickets.de/?ch=call2bookagentctde
Germany: http://www.flugladen.de/?ch=call2bookagentde
Ireland: https://www.vayama.ie/?ch=call2bookagentie
(Important note: It’s not allowed to share this link with customers!)