Eder Alvarez Balanta – River Plate – 8.75-10M – Prob one of the best if not the best on the game
Thiago Cassassola (Not sure of spelling of second name) – Boca - Available for 1.3m first season, not sure of second
Marquinhos – PSG – available for around 20m
Also Umtiti is apparently very good but never used myself.
One of those alongside Jones should be your defence for many years.
Take a look at Balanta before you sign him. Sometimes, his stats are monstrous, other times, he can become a liability, even.
Marquinhos is ultimate quality, very, very consistent, if a tad too overrated. But I doubt if he'll be available for that price.
Umtiti is an excellent option.
Ideally, Doria, Umtiti, Balanta are your best bets, with that much amount of money. They can partner Chris Smalling, cause you ideally should be using Jones at RB (he's more of a beast there than CB, unless you bought Peruzzi.)