Everyone but you has a 10GB plan for MB.. at a reasonable price! Your latency times are a weee bit better than Bell, your only nearest competitor in that area.
For example, Rogers has 10GB for $75 ($70*), and 15GB for $85 ($80*)
* If you bring your own device
MTS is unlimited.. in MB only.
I'm sure that if you could match, or better Rogers' prices, your customer base might actually grow. Also, fire the ones that decided MB didn't deserve a reasonably priced 10GB data plan.