[Linden Dollars?]

Oh... and if you actually did use the LindeX then the answer you need is in the Knowledge Base. 

http://wiki.secondlife.com/wiki/Linden_Lab_Official:I_bought_Linden_Dollars_(L$)_but_my_balance_hasn%27t_updated!

Take a moment and consider:

You're asking a question which needs an answer: Post it in Answers

You're asking a question which has been asked a million times: Search the Knowledge Base.

[Linden Dollars?]

Okay... you're not sure whether you used the LindeX (official) or a 3rd party exchange (unofficial).

Check your PayPal to see where your payment went.

[Linden Dollars?]

Did you purchase the Linden dollars using the LindeX or did you make the purchase using a third party exchange?

[Is it possible to reduce the monthly payment on a private region (island)?]

Gosh.

Besides the US$295 a month for the island you're also going to be charged US$1000 for the creation of the island itself.

As you're getting no response from LL you should change your credit card information under Billing to a dead or expired card so you don't get charged for the island you accidentally ordered.

You should also phone your bank and tell them to halt all payments to Linden Lab.

In the future you might not want to randomly clickety click buttons but instead take the time to read, understand, and comprehend what you're doing.

[How Do I pay someone when I can't log into Second life?]

You might be ghosted.

Open your Preferences > General and see if switching Start Location from Last Location to Home Location will get you into a different sim.

Also, try clearing your cache under Preferences > Network.

[How Do I pay someone when I can't log into Second life?]

Create an Alt and try logging in using that. If you can get in using the Alt then

a) purchase some Linden dollars and pay your landlord *make sure to tell them you're the Alt of another account

or

2) contact your landlord by IM and ask them for their email address so you can attempt to pay them by PayPal.

Can you elaborate on the login failure?