then how to promote unlimited 512kbps?

It is really unlimited if you only use it on your phone and isolate your home network WiFi on a fixed line instead.

No sane person will use more than 50GB on a phone if you're working or occupied with healthy activities outdoors. 5 hours a day non stop with movies on a small screen? Dont tell me you got NBTD and your phone battery can last that long streaming.

technically, 512kbps is unlimited. how to remove the unlimited?

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In the selling of services or products to consumers, there is the "reasonable or fair" consideration for the service or product. In this day and age, using Internet data at 512kbps or 0.5Mbps d/l speed cannot reasonably or fairly be considered as unlimited data. 20 years ago, can la, eg  when there was only TM Streamyx fixed copper Internet and no HD video quality, eg unlimited data 384kbps home plans at RM69 per month using CRT monitors.

It is cheating if a business sells a bottle of ordinary tap water to a willing amnesiac rich old person or gullible rich child for RM100, if such a case is taken to court.
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ban