no wifi on maestro

That must be frustrating.  So sorry.

Some questions;

-  What company did the repair?  They would be in the best position to support your question.

-  While Flex uses a Dell Tablet internally, it is very likely customized with specialized FW
   or options that Flex needed to make the Maestro work.   Make sure whoever fixed it and put
   a new tablet inside knew exactly what Flex needs in order to work fully.

- It would be hard for anyone to figure out how to answer you unless there is a lot more detail
to the post;

1.  Who fixed it, and are you personally able to verify that they did use Flex specific parts, options, and firmware that they got directly from Flex, and not from Dell?
[ If they simply purchased a similar Dell tablet, and not from Flex, that would be why it does not
work.  I have worked for a large computer manufacturer for the last 30 years, and it seems we
are changing chips every 90 days, even sometimes without changing the model number of
the computer.  This is due to spot market, supplier, and profit issues.   But a commercial customer
like Flex can have a custom part number with Dell to ensure that things do not change.]

2.  The person you paid will have the above information and should be responsible to either fix
the problem or refund you, since their repair apparently did not work fully.

Best wishes, and sorry again for the frustration.

Neal