Questions:
how much of each week is he missing at college? A lesson or two, or a whole day or two? Are there reasons for this? A course he is avoiding. One of ours did exactly this for their first year at college and similarly didn't have EMA for weeks and weeks, and no money from us either. Didn't bother them. We never restricted use of the computer (partly because it was a shared computer!) because if there was work to do for college, they needed it for that. In our case, it was a hated college course they wanted to drop, which they did, after AS level. Once the second year of college began, they realised they had wasted an entire year and knuckled down to work. They are now at university studying a subject they are really keen on and doing okay.
We did have several discussions with the college, many many talks with our child about their age, their responsibilities, their wants and hopes for the future. We were very heavy on the likelihood of "no future jobs at present, long-term unemployment (not easy at any time) so the necessity of continuing in Higher Education for the moment".
Talk about the support and contribution that each person in the family should make - even if it's not much to start with. For someone who has been a pita for a while, it will take baby steps for them to start living up to behaving in a more adult, responsible fashion. Ask them to do something they can achieve and will likely agree to do (and will actually do) for a start.
Personally, I would not have stopped cooking for our child because eating together makes for a time of socialising with the family, and shows there is still parental care happening. It would feel like the parent cutting ties of kinship and communication (regardless of the fact that the child is doing this as well). Treating them like a lodger might make them feel that there is no longer any bond between you so they have nothing left to live up to.