Getting SEN help at school and college

Can anyone give us some advice? I'm a parent of a recently diagnosed autistic 16 year old. Our son was chewed up and spat out by the school system, we really struggled to get any help as he really struggled with anxiety and with physically going into school. The school were useless and just wanted rid of him, so in the end we pulled him out and home schooled him as best we could while both working full time through his GCSEs. All the while waiting for an autism assessment.

He's since started college and we're seeing the same pattern repeat itself. We're finding it impossible to even speak to the college SEN department. Other than going and camping myself in the college reception until I can speak to someone. Anyone any advise on what we need to be doing? We are slightly at our wits end.

Thanks