If you are not interested in proceeding with the marriage why did you wait for 1 year to take this decision, you should have conveyed your disagreement to the girls parents a long while back itself.
If the girls father has paid cash for what ever reason, and is now refusing to provide his bank account number for you to do a refund of the cash amount, my advise to you would be to procure a demand draft equivalent to the cash component received by you and your father and send it by registered post acknowledgement due to the girls father.
Without any undue hesitation inform the girl and her parents that you are not interested in the marriage, spare the girls and your life of untoward misery and suffering after a forced marriage.