"Portable" means TM, the owner of the IP block, can move it to another network.

It has nothing to do with you and has nothing to do with your issues here.

It's a coincidence.

When TM applies to APNIC for IP blocks, they ask for either portable or non-portable space. They are a large national ISP, so whether they get portable or non-portable doesn't make much difference in this context.

At one point they applied for block X, and ticked the box to request portable space. They put block X into service and configured their routers to handle it.

Later they applied for block Y, and did not tick the box to request portable space. They put block Y into service and configured their routers to handle it.

Block X and block Y were configured at different times, probably by different people, and probably on different equipment. All these factors (time, staff, equipment) may be significant to whether or not block X performs better than block Y. The portability of the allocation block is a red herring and has nothing to do with anything.

All this will do is ruin facilities for other people and possibly help you get to jail. It will not prove any point about TM's problems, it will only show that there are hooligans attacking them.

If you don't like the service at a supermarket, do you think you will improve things by setting the building on fire?