Whitehat : No need warm up. Blackhat : 2 to 3 days warm up, but even then, success depends on campaign set up skills and campaign warm up related skills and various other factors as well.
@Briorix mentioned "I am doing whitehat and every time I create the second campaign "Suspicious payments" ".
In that case there are a few possibilities :-
1) As per you it is whitehat, but in reality as per GAds policies and GAds review alogorithms, it is not whitehat.
OR
2) It may be whitehat, but your (2nd) campaign's incorrect setup and / or landing page related issue, triggers the suspension.
And to be pure honest with you, without taking a look at your campaign and landing page, no one would be able to correctly identify what triggers the account suspension(s).
NOTE : Suspension reason as due to suspicious payment (as per GAds) : In most of such cases, in reality, the account suspension has nothing to do with billing, payment, card, etc. Even campaign, niche, landing page issues, etc can result in account suspensions with GAds mentioning those as due to suspicious payment.