I been gone a while do to work and school. I Finally got back on and i cant open anything in my house. It says " Residents are not allowed to switch here". I thought maybe I lost my house somehow. So i went out and got some things to sell. Now I cant even sell anything. I typed /Sell (Item) (amount) and /Sell ( amount) (Item) and I get " You are not authorized to use this command". whats going on? If I need to start over and make a new home and all thats fine but I cant do anything...

You might have lost your house because in most towns a plot costs about 10 nbz a day (which is automatically paid via the towny-plugin). If you can't pay anymore Towny automtically takes the plot away from you. It is basically a feature to prevent towns from being full of abandonned ghosthouses of inactive users.
In most towns you can easily reclaim your house by contacting the mayor or one of the townassistants.

/sell didn't work for you because the servershop was deactivated for a while after the last patch. The plugin that controls it had to be updated. As an alternative there is a marketdistrict at /spawn where you can sell items (often for a better price than the servershop).

Some towns also offer their residents ways to earn easy money, like wheatshops (or sugar) at the towns farms, so you can harvest and sell wheat easily. In most cases the only rule for them is that you need to replant.
If your town doesn't have one you could always ask TwistedLover (DragonFire) or BuckieUK09(Glasgow) to use theirs.