of vs on

Could someone please help?

of is correct.

You state 'tyre', indicating that you might be British.

I think that this question of usage depends upon your nationality. In the US, 'of' would be more prevalent. But 'on' I do not have a problem with, and this might be my recognition that 'on' (the topic of) really does indicate what topic the suppliers are needing confirmation of (or 'on'!!!).

There are slight differences between US English and British English and, even within either's regional environment, there could be differences. For example, I pronounce 'often' without the 't'. Many in the US pronounce the 't'. - David Lyga

The orders have already been made. Therefore, buyers are being notified on prices made on those orders.

Or

It could be “ about price increases “

Of is correct in the UK.