it would be perfect to have a look at the logs, printed by the backend, in the shell from which you run cle-start.
How have you verified that the TF stops running after rosservice call? Have you tried putting some clientLogger.info('ALIVE!!!') in the TF?
Anyway, it is not recommended to bypass the NRP and call gazebo services directly, it may lead to unexpected results.
The way to programmatically use the NRP is the "Virtual Coach" python interface that allows you to run scripted experiments.