It's almost instant. You can find the account information in your mailbox and log in account right after your payment.
Sure, the account will be yours forever and you can do anything with account after your purchase. We are the biggest and most trusted MMR Accounts seller in all servers. You won't find any seller which have more accounts than us.
After last several updates, some of the users (especially users with multiple accounts or lower than 8000 behavior points) has been put into special queue by Valve system when they use new account that didn't login to their PC/IP address before. This based on the factor that the new account didn't have activities record on your PC/IP address yet. To fix this, you simply just need to play unranked matches constantly for 1 week, after that you can find ranked matches normally cause the account now already had your activities record on the account.
Also please remember to follow the Article '' How to use Dota 2 account'' and complete all the steps we give you there so that you can avoid most issue because of playing a new account.
Recommended Accounts are the best choice so make sure you take a look at them before giving any decision.
You just need to login to the website using the email you place the order, then follow this link to send the account info again to your email: https://www.vikingdota.com/pages/my-accounts