Unfair Business Practice

I am very disappointed with this company, I bought a vehicle through an auction bid that was placed on Friday the 5th January 2024 in the afternoon and I received acceptance of my bid that Friday afternoon. Taking into consideration that Saturday and Sunday was a weekend, I however made means to ensure that I made the payment within the 72hours as I was advised. The payment was effected on Sunday morning and proof of payment was submitted on the very same day on the Sunday. Now the company sales person is telling I will forfeit my deposit and they will refund me purchase balance that I paid on Sunday only. This is a **** and I see the vehicle is being auctioned again at a higher price. where is fairness in this business deal?