You don't receive any additional credits for leveling once you reach the "golden" levels. This is as intended.
so why before update i was getting for each lavel 1000 credits on heavy after 70 and enforcer after 30
Those were the old maximums before they added prestige ranks (gold) up to 1000. No additional credits for prestige ranks unfortunately. Bragging rights only.
Because you either remember it incorrectly, or you had a very favorable BUG on your side that no one else reported about yet, or because DICE loves you and is giving only you this bonus.
Well, jokes aside, F8RGE the community manager presented the prestige levels making it clear they would not give any rewards except a golden badge with your level in it for enemies to see whenever you kill them. So unless something very weird happened, you never got any credits from those.
Nevertheless, these prestige levels shouldn't award credits and therefore you not gaining the credits for prestige levels is the correct behavior by design.
