S430 doors wont open or lock car wont start
 

I recently purchased an s430 4matic 2003 used and within 2 weeks the key will not open the doors, and when I tried opening the door with the small key the alarm came up and the smart key will not start the car or turn off the alarm.

It happened once before and the car started after a few minutes. I told the dealer who said it could of the battery of the smart key. I replaced the battery of the key and ordered a new key but still the problem persists using both keys now the car wont start the key wont even turn in the ignition like the ignition is locked.

The car battery is good.

Can anybody help?

Thanks in advance