Every telco will bill one month in advance. Eg my M1 bill dated 2 June will bill from 2 June to 1 July plus whatever extra usage charge incurred from 2 May - 1 June.
Zero1 seemed to send their bills late and on irregular dates but when I checked their bills, everything ok so far. Eg for 1 Apr invoice date, it will show billing period /current usage for 1 Mar to 31 Mar and advance subscription for 1 Apr - 30 Apr. Nothing wrong with this.
I recently terminated my Zero1 line by end June (as I have too many lines already), so far no issue with over billing yet.
Sent from REDMI NOTE 5 on Rocket Uno with TPG Booster using GAGT
All this started after they migrated to the new billing system. Those who opted in for roaming get theirs migrated earlier and those like me who didn't eventually were also migrated. Prior to this, billing is also the same i.e. previous month excess usage if any + current month.
Yes every telco bill in advance but Zero send their late despite the bill showing dated correctly. Using actual example, 01 March dated bill sent on 11 March and was for Feb excess usage and March advance billing. So this was charged to CC and paid.
Then came the hooha. Sent bill 01 April dated bill on 30th April but show charges is for March when it was already paid. Fine, they subsequently send an email to inform us to ignore and did not charge to cc. Can see its using the new billing system as the format is different.
No bill was sent in May.
Then on Jun 22, they sent a bill dated 01 May and in it show the error I mentioned earlier. Double charge for April and May advance payment when it should be for Apr, May and June since it's 3 times the amount.
So the error carried on to 01 June dated bill received only on 11 July. It shows its for June advance payment.
So as can be seen, on their books, one month paid is missing even though in terms of actual amount, we have paid up to date i.e till July so there's actually no lost but when it comes to the time to cut off e.g. if I terminate yesterday 31st July, on their books I still owe them July payment. If I terminate much later, can imagine how much we have to trace back. So guys keep your receipts.