OK I called my cell phone provider (metro pcs) to drop my phone bill down to the $35 plan wich is long distance and text messages.. that night my boyfriend called my house phone instead of cell cause my phone now says that I am unavailable or travled outside my coverage area.. I'm still at my home wich my phone has worked here for 3 years so there isn't a travel outside coverage area possible.. I called the phone provider and the say they didn't cause it.. and don't know what is wrong.. I can call out and send text messages out but can't receive anything back. I can't call my voice mail either it gives me a busy tone instead.. does anyone have any idea what is wrong and what I might be able to do to fix it? Or do I need to just buy a new phone

Wait a couple of hours and try again. It could be with the changes in the plan, that the system needs to be re-configured to accept your changes. And although this is all done by computer, it still takes some time for it to take affect. If, it doesn't work tomorrow, then go to an actual MetroPCS store, not a re-seller, and tell them what is wrong. Have them try to call your phone. You might need a softweare update, that they can give you there, or it may just be your phone, and they can give you a rebate towards the purchase of a new one. But I am thinking, (And I used to work for Sprint PCS in customer service,) that it is probably a tower issue, or a software upgrade. Hopefully it will be working soon. I have Metro, and sometimes I cannot connect, but if I wait a little while, or go to a different cell, it goes right through. Good luck!

Please read an entire post before you decide to disagree with it. I did not know that this was "Yesterday". If I did, that would have changed my answer. Cell towers are not perfect. They can fail. I have had issues with outgoing and incoming calls with my Metro, and my Sprint phone. Changing towers seems to help.
Again, it could be that you need a software update, so that the towers can communicate with your account. If you are not satisfied with the answer that Metro gave you, wait about thirty minutes and call back. You'll get another representative, who might have a bit more knowledge than the first guy. If that fails to work, go to a actual store, not a re-seller, and see if they can help. They will have access to more information about your account than a re-seller does, like what cell is your home cell, etc.
That can help them diagnose your problem. And, if it is your phone, it will be easier to exchange it and get a new one. I'm thinking the change to your account put a block on your phone, that they either failed to look for, or cannot change. I used to do this for a living and I have encountered it before. The company didn't do a thing, but the software automatically flagged the account, and put a block in place, because of a 'possible fraudulent change'. Not what you did, but the software was designed to look for major changes and flag them. We would have to override accounts that we would normally not think would get flagged, like for downgrading a plan, but they did.
Call Metro back, and if they give you an unsatisfactory response, ask to speak to a supervisor. They should be able to help.
Good luck!