QB doesn't download data from my bank (error 102). I don't know when it will be resolved. If I download manually, will transactions get double entered once issue resolved

I can see the urgency of getting this resolved and I'd love to get this sorted out for you, sunshinebrandsll.

To get started, can you please verify the bank account name which is encountering an error? 

An error 102 occurs when QuickBooks Online (QBO) is unable to establish a connection to your bank's website. To get this fixed, you'll want to manually update your bank. 

Here's how:

1. In the left menu, click Transactions or Banking.
2. Go to the Banking tab and select the appropriate bank account.
3. Hit the Update button. 

Repeat the above procedure for at least three to five times to ensure your transactions.

However, if you'd want to have the transactions be available on your QBO account, you can manually upload it in the system. And you're right that once the error resolved, it'll download transactions. When that time comes, to avoid duplicate, you can exclude downloaded transactions.

1. In the left menu, click Transactions or Banking.
2. Go to the Banking tab and select the appropriate bank account.
3. Choose the For Review tab.
4. Select the checkbox of the transactions to exclude.
5. Select Exclude.

For more details about the information above, see below articles:

• Fix bank error 102 and 105
• Exclude a bank transaction you downloaded into QuickBooks Online
• What to do if you see a bank error or bank transactions won’t download.

Once bank transactions downloads, you can now start categorizing or matching them to straighten out your books. After that, you have the option to do your regular bank reconciliation. 

If you have additional assistance while managing your bank transactions, let me know. I'll be around to provide further assistance. Have a nice day.

I have already tried all troubleshooting and it doesn't work. I keep getting the attached message. I also called my bank. There is an issue on QB end. 
My question is: if I start downloading transactions manually, am I risking transaction duplication down the road?

Yes, it's possible that you'll be encountering duplicates, sunshinebrandsll.

You can exclude the duplicates along the way. The steps were provided by my colleague above on how to do so. I'll share the link again as your reference: Exclude a bank transaction you downloaded into QuickBooks Online.

If you get the same thing, after manually updating the bank. You'll want to disconnect the account and then, reconnect it again so it starts downloading transactions. Just ensure that you added needed transactions from the For Review tab since they'll be deleted once you disconnect the bank. 

Here's an article that will help you on what to do if you get a bank error or can't download transactions in QuickBooks Online.

Let me know how this works so I can walk you through from there. Take care and have a great day!