installation error: unable to connect to MySql database

[yaroplane]

Hello,
Instead of installing the main SEF Component I unintentionally installed the patch (for SEF for Joomla 1.5.14), via back end's install/uninstall feature. Now I can't connect to MySql database; I don't have any access on the back end either, the whole thing is screwed up! I get the following error on both front and back ends: "Database Error: Unable to connect to the database:Could not connect to MySQL". any idea how to fix it?.. I tried uploading the undo patch files via FTP, but that didn't help. I am desperate, months of work are gone... help, please!
thank you in advance! 

[joomlatwork]

Sorry but the email is not known at us. If this is related to the paid SEF patch component either email us or POST with the purchase email address.

If related to the FREE patch: This cann't be installed or deinstalled, this is not possible since this is not an installable component. So I don't understand how you have done this.

Regards,

Richard