How useful are CCTVs? A first hand experience

My son, Jay had gone to the Lake Town Branch of Axis Bank to deposit some cash and cheques.
While filling in the deposit slip he had kept his Cellphone on the counter to jot down the account number from the phone. While writing he just turned to ask a query and when he turned around, the cellphone was missing.
Only person at that time was the security guard of the bank and one other customer.
He complained to the bank but they exclaimed that nobody in the bank had taken it and wouldn't know if a customer may have taken it. jay tried tracing the phone by calling it, but by that time the battery was already taken off and hence the phone was not reachable. Dejected at losing the phone, jay came back home after finishing his regular banking activity.
On listening to the story, my wife suddenly suggested that the bank should definitely have CCTV installed and the theft should have been captured on the footage. I advised him to register a complaint with the local police.
He went back and asked the bank officials to share the CCTV footage for the specific period, to which the bank officials denied any co-operation. However, when he managed to coax them with a threat to involve the police. The bank officials however said that they did not know how to operate the CCTV and hence Jay would have to wait for a day to get the result. Jay submitted a written complaint to the bank officials requesting co-operation. The bank officials said that they would get back to him by two days. It was apparent, that the bank officials wanted to ascertain that none of their staff is involved in the act.
Within 4 hours itself, he received a call from the bank stating that someone had returned the phone back.
I am happy that my son got back his phone. But a few questions worry me.
1) When the bank was covered with CCTV why didn't the suggestion come from the bank to have a look at the CCTV footage?
2) When my approached the bank why were they recalcitrant in sharing the footage giving one excuse or another about the CCTV was outsourced and it would take two days to get a report?
3) How did the bank then get back the phone within 4 hours and inform my son to call on them the next day at 11.00 am and collect the phone?
4) What action have they taken on the person who pilfered the phone?

The matter should not be taken lightly.If one of their employees was involved, as I suspect he should be charge-sheeted and sacked.
Theft is a serious offence as per Standing Orders of any organisation, especially Banks where large sums of money are involved.