Colleague Ignores Requests

I've been working for this new company for 9 months now..after my job of 5 years was eliminated last year due to a structural change.. so I am well versed in this field.

There are some items that I am still learning considering it's a new company and that's to be expected, no problem.

I am having an issue with my colleague not respecting my time (whom I've now taken over for she has since retired but working contract to help out until the end of Q1 2022... it's a 1 person role). Maybe I should refer to it as something else but let me explain. It's a pretty busy role so I am quite booked daily. She will call with little or no notice at all and take up at most 1.5 hours of my time and sometimes 2x a day...not considering that I'll be working on other items. I've politely asked her to schedule meetings especially since they're never short. She says okay but then doesn't actually do it. I've asked via email, phone, and instant messaging. This has been an on-going issue and I'm not sure what to do now. Her doing this either puts me behind for other reports I need to get done or I have to start over especially if I was in the middle of running numbers. I've tried not answering her calls and sent an i.m. asking for a couple more minutes to find a good stopping point but she just calls right back.

Any suggestions for this?

I'm trying to keep away from going to a manager about the issue because it's truly minor but I'd definitely like some advice.