Something I have never seen from any network is an annualised amount of Data i.e. a once-off payment for a large amount of data usable for 12 months from the date of purchase. I have seen small amounts of data available for 3 months on UK networks but not bulk amounts over 12 months. The advantage to TM would a significant reduction in costs and administration with bills/direct debits/losses from unpaid contracts etc and of course it gets its money up-front at the same cost of an everyday top-up.
A 'small' package might be 100GB/€95.
A 'medium' package of 300GB/€195.
A 'large' package of 600GB/€295.
I am sure something like this would find a market. From the consumers viewpoint the advantage is that they do not have to be checking their usage to stay within their data allowance every month, rationalising their usage to stay within monthly allowances and having 'wasted' unused data allowances during holiday periods etc and the bank transaction costs of direct debits every month.
Any chance of any feedback on customer 'feedback and suggestions' btw?