Accepting Offer But Not Joining

Hi Guys,

Most companies send an Offer Letter and expect to accept within 7-15 days and we are accepting it as well. But later if we get any better offer we try to negotiate with the 1st company if they are not matching then we are joining which one is paying better.

My question is what will happen to the 1st company where we have accepted the offer initially.

Will they blacklist for life or the cooling period of 6-12month?? Which is it ?

(Companies like INFY, CG, COGZ, ACCENTURE)