It is puzzling where could the cheque gone to ? blown by the wind during collection time ? Bank staff collected and threw it accidentally with some rubbish ? Mounted at the wall gap in between the box ? landed on floor and stick to someone's shoe and transported it elsewhere ?
The cheques are removed from the locked box by a bank officer & brought to the back room...what is the procedure these days, I can't comment, for I have not been working in a bank's back room for ages. There are still human errors to be made, misplaced the cheque? or due to the person in charge of emptying the cheque having a bad day etc..
Best, like someone suggested, you want to make sure that, that cheque gets cleared...however long the queue is at the counter, get it deposited over the counter...you have on the spot verification & printed proof. You should have check your account on-line, one day after the cheque was placed into the cheque depo box...it should show the amount on hold.
Off the tracks....some years ago, I was in Penang, went to one of their banks lobby to withdraw cash & noticed a cheque deposit machine that had a screen...you deposit the cheque into the slot, it will scan the cheque & display it...dunno, if it will print out a copy for you as an evidence of depo or not, but it will issue a receipt, accepting the deposit of that cheque, that shows DEPO machine number, time date, location etc.
Have not seen one in Singapore to date...the only ones, we see are those with the slit of a slot...like 'voting is secret'...anyway, you should ask for a CCTV review...but it may cost you time & maybe money...& may have to make a police report...if it is for a $50 cheque..forget it...unless it is pay to bearer the amount of S$1,000,000