Can't Join Calendar

I'm having an issue joining my works shared calendar.

My boss originally sent me the invite to my works address and I joined no problem, but then realised I had done so with my personal iCloud account and I wanted my works mac to be set up with a different iCloud account.

I deleted my personal iCloud account from my work mac, and deleted the calendar from my personal iCloud account. My boss then deleted me from the work calendar and invited me again, but everytime I try to join it it comes up with an error message telling me I can not join as the calendar is no longer shared.

Can anyone help?

It's important for me to be able to see this calendar in order to do my job!

Thanks.