This is a regular procedure for service provider (in order to figure out if you indeed want to port out the phone number). But you don't HAVE to cancel with them (if you cancel before the porting it will be a failed one).
If it is showing a 5420KB of usage that means the data is buffered (and ready for use) but it not means you already used it. Might be the most relevant sign your data is working, and for what is buffered, if not used, will be eventually stored back (...