There are several reasons to get a temp ban in d2, the rules are rater crazy. But it mostly boils down to making to many games to fast, the good old days just farming Meffe over and over are gone or going in and out of alot of games to mule. Temp bans normaly start with 5min and then go upwards untill hitting the maximum of 12 hours.
The way D2 works is of your IP adress. So if u got an options with your ISP to get a new Ip simply by rebooting your Router thats an option to get around it, thoe abusing this will make the rules even harder and make it even more easy get more bans.
Best way to avoid thies are simply staying longer in each game you create, do several things when farming like a few act end bosses + dia/baal runs before making a new game.
This is a fansite, not affiliated with Blizzard in any official way. Some others have already given you helpful advice, but the "correct" way of doing this is to submit a ticket to Blizzard support. On the battle.net homepage there's even a "support" button on the top right, that's the way to go to get an official answer.
Also, I've removed your double post (please don't spam the topic multiple times) and post in the correct forums.
Last but not least an important note: It has come to my attention that you've sent PMs to random (non-mod) people on this forum. In general, asking for help once is fine. Spamming your request in multiple forums (in the wrong sections) and randomly sending PMs to multiple people is not a good idea - it's the typical behavior of a bot, so our spam system might target you. And of course spamming in general is a frowned upon activity in the Internet in 2016 in general...