mass airflow sensor

Computer check revealed rich fuel and oreillys tol
me the mass airflow sensor was the oroblem. I
first tried to clean it but the same problem arose
which was car dying while driving with no other
problems. Car ran smooth idled fine but once in
awhile it would just die at any speads. I got the part
from buyautoparts.com and changed it. Now my
car sounds rough and there's a huge puff of white
cloud that comes out the exhaust. I put back in the
old mass airflow sensor and the smoke is no
longer present and the van runs smoothly but
engine light still comes back on. I haven't ran the
car longer then a couple minutes with the new part
because I worry that there part is gonna cause
damage to my vehicle. They are standing their
ground that their part is the right part and saying
something else is wrong with the vehicle. However
if that was the case then why is the problem
resolved when I put in the original part on? Should I
allow more time running the vehicle with the new
part and actually test drive it to warm up the car or
the fact that it sounds rough and has the huge
amount of smoke coming out of exhaust suggest
that there part is the problem and shouldn't be
driven with the new part? If they in fact did send
the wrong mass airflow sensor will it cause
damage to drive with it?