oven problems

My landlord replaced our gas oven/stove about 6 months ago. Pretty much since then, we've had problems with baking things like rolls, biscuits, cookies, etc. These always come out burnt on the bottom and slightly underdone to just barely done on top. We have the rack slightly above the middle so I guess we could raise it a bit more. But I'm not convinced it would help that much.

I suspect it's just because it's a super duper cheapy oven, but does anyone have any thoughts? I just baked chocolate chip cookies and I don't like burnt bottoms!!

Insulated baking sheet? Silpat? Trade for my super duper cheapy electric oven/stove with the unspeakably vile cast iron burners?

Does the regulator appear to be adjusting the temperature properly?   i.e. Can you see the burner reducing the flames once it nears the correct temperature for the setting you've selected? 

Sorry for the late reply... I needed to try and see if I could answer you...

I think it is working... when I have the temp set low, it is low, when high, it's high.

I had this problem with my oven back in the states. Just use a lower temp than the recipe calls for. For example, if it says 375F for cookies, cook at 350F. Also, if they replaced your oven with a fan type, rather than gas, be sure to cook at 20C less for everything. You can also get a thermometer to place in your oven and test that the setting and actual temperature match. That can help you figure out how much of a lower temp to cook at.

An oven thermometer was to be my next suggestion if the regulator appears to be adjusting the burner properly.   You can place it on the various shelves to see how the temperature varies throughout the oven.  It may well be that with a cheap design the temperature gradient is steep, with upper levels being considerably hotter than lower levels.