Cable modem, blocks and MAC/IP address

Hello,
Now before you post anything please don't tell me to talk to my dad, get a life etc. i am here for help please guys and gals not a lecture!

I am 20 years old and living at home (unfortunately) with my parents and pay rent. the issue is that recently me and the old man had a fight and he has decided to cut the only thing that means anything to me which is the internet. as ive got mental issues and getting over a drug habit this is the only thing that keeps me sane!

first of all i want to know how he has blocked me from using the internet.i'm still hooked up to the modem but cannot use net. i can change the MAC address with a dodgy program and get it running but it doesn't seem to last for that long.

so for example....
if i kept changing my MAC address will the modem just see me as a new user? or i need to change my IP to?

whats the dif between IP address and MAC address?

can you help me out on ways around this issue?

is there anyway of accessing the modem without showing up on the modem log?

what the old man doesn't know wont hurt him and hes just trying to pull some power trick on me

thanks for your help guys, as u can understand this is immensely frustrating and will help me out aallot if u could throw me a bone

appreciate it!