بسم الله الرحمن الرحيم
In the above mentioned case, if the wife switched off her mobile whole night as per her saying whether she switched it off for changing SIM Card or due to unavailability of balance, in each case the condition was met. Hence one muallaq talaq given by the husband occurred. It is talaq rajai. If the husband wants to take her back, he may take her back during iddah period. There is no need of new nikah or halalah. If the iddah was over then it is necessary to do new nikah with new mahr.
Note: And if your wife did not switch off her mobile whole night and she switched off her mobile only for some time to change the SIM Card, then no talaq took place. (N)
Allah knows Best!
Darul Uloom Deoband