Two quick comments...

Whatever 'protection service' your ISP will offer you will be utter rubbish and grossly overpriced.


The Malwarebytes software is only a one-time 1.7MB download and their updates normally take no more than 10-15 seconds from start to finish.
However, you are very correct about running the ESET on line scan... That would eat up your allocation/cap.

I urge you to do the Malwarebytes instantly !
The ESET scan was only suspenders to go on top of the belt !!!


Whoa !!! It just hit me !!!

You have a 56k dial-up with a bandwidth usage restriction ???
That is outrageous. They are cheating you, very badly indeed.