Key Fob broken and driver door lock not inserting or turning the key to open door?

I have kept the driver and passenger door unlocked for almost 2 months (since May 26th) in order for me to get inside my vehicle and I am wondering is this what landed my ignition switch to lock up June 15th. Keeping me from turning the key over before I changed the ignition switch June 20th which now it turns over to start but it shuts down after trying to start it. It was put on a machine which said the key needs to be coded, although the mobile locksmith said the key is invalid, don't know if his coding system says it or if he said it on his own because the key won't take the code to my vehicle's computer. He also said it was having a hard time accepting my vehicle VIN, he couldn't find the security system or anything maybe it's in the body control module, but I do not have money to keep spending if I do not know the problem with the vehicle. It turns over but won't stay cranked. Please help me!