IMHO, requiring customer support is fantastic.
I would be happy to pay extra for the privilege in the form of automatic annual licensing, or having to buy the theme again (after one year) should I require support.
As many online business owners, I pay monthly and annual subscriptions for online apps, Wordpress plugins, themes and other misc software.
Sure it adds up, but if the software is vital to running your business, it is worth paying to keep up to date.
This will most likely be your ISP restricting your connection.
Sometimes when you suddenly start downloading large amounts of data (like big PSD files) they will limit your connection speed to stop you abusing their service, especially if the large downloads are seen as unusual activity.
Try waiting for an hour / resetting your connection and then downloading again. If you keep clicking download download download you could aggravate the problem.
As mentioned above, the expiry date is for accounting reasons, the same as any high street retailer would do with a gift card.
The expiry date isn’t there to force you to spend your money quickly, more to clean up accounts that are left with $1, 50¢ – small amounts of money in and never returned to.
If your deposits do expire and you’re still active, waiting to use them, simply contact Envato Support and ask them to reactivate your money.