Reading the 10-digit tag id correctly
The tag id is the long number on the back of the card, and it is digits only — no letters, no spaces, no dashes. Cards carry other shorter numbers too, which is the most common reason a request has to be sent back. Count the digits before you submit: exactly ten, and you are fine.
Why there is a daily cap
Three requests per card per day sounds arbitrary, and in a sense it is: it is the point at which a pattern stops looking like a commuter and starts looking like something else. The cap protects the card holder more than it protects us. If you genuinely need more, one larger request up to AED 500 is the simpler route.
Where the waiting time actually goes
Almost none of it is technical. A top-up submitted during working hours is usually credited within half an hour, and most of that half hour is the payment clearing. The long waits happen when a request lands in the evening or over the weekend and sits in the queue until an agent reads it the next working morning.