Thanks for joining this thread, @Stephbrown1. I can't imagine what you've been through when you lost your credit card. I'm glad you're able to change the number right away.
 
Since you got a new one now, you can edit the bank feed settings for your credit card account in QuickBooks so you won't have to download your transactions every time. First off, you'll need to deactivate the bank feeds for the old credit card. Then re-setup the new account. Here's how: 

Deactivate bank feeds in QuickBooks Desktop for Windows

1. Go to the Lists menu, then select Chart of Accounts.
2. Right-click the credit card account you want to deactivate. Then, select Edit Account.
3. Click the Bank Settings tab.
4. Select Deactivate all online services, then click OK to confirm.
5. Click Save & Close.

Deactivate bank feeds in QuickBooks for Mac

1. Go to the Lists menu, then select Chart of Accounts.
2. Highlight the credit card account, then select the Pencil icon to edit.
3. Click the Online Settings.
4. In the Download Transactions drop-down, choose Not enabled.
5. Click OK to confirm.

For more information, check out our help article: Edit Bank Feed settings for bank or credit card accounts and follow Step 3 to re-setup the account for Bank Feeds.

With regard to your saving file concern, if you're unable to save your bank data as .QBO file on your end, I'd suggest you contact your bank and verify if they can provide you a .QB file. If this isn't possible, contact an IT guy to help you convert data. Then, follow the steps provided by @matts on the 1st page of this thread. 

Let me know how it goes, @Stephbrown1. I'd like to make sure that everything works perfectly on your end. We're always around here to help you if you need assistance.