Revised data package size prevented roll over of unused data.

For the past few months, I have bough the 200Mb 30 day data package. Provided I buy the same size package just before the previous one expires; the unused portion is rolled over into the new 30 day period. Without warning, the 200Mb 30 day data package has been discontinued and replaced with a 240Mb 30day data package. Because I could not buy an identical size package as before; the unused portion of my previous 200Mb package fell away. This is a grossly unfair practice.