You shouldn't use your alt accounts except here on meta, or your alt accounts could get banned as well.
The ban on your main account could also be extended for ban evasion.
I am using it from a different browser. Won't that be okay?
No. You personally are not able to post/send PM's during the time that any of your accounts are banned from any of your alt accounts with the exception of posting in Meta.
This rule really should be posted in a more clear manor but it is the rule (ban evading)