Visitor record expiry vs Visitor visa expiry

[LeoQM]

I applied for a visitor record before the expiry of my visitor visa and received it a few months later. During that time I flew to the US for 10 days and came back with my multiple-entry visitor visa. I am wondering if I am supposed to leave the country before the date specified on my visitor record or six months after I arrived in Canada (since I did not get a dated stamp on my passport on re-entry). The visitor record is valid until next fall while six months after my re-entry will be in march. I contacted IRCC over a month ago but have not heard back.

Thanks