Listing Titles Rebrand

Hi, we're rebranding our store to another brand that we own, this has been registered in Amazon's Brand Registry. Seller support have said they can update the brands to existing listings (well, they can pass to another team to do this with an unknown timeframe) which we have set in motion.

Our listing titles currently have our brand name pulled in even though we haven't entered it and when trying to get further information from Amazon, I'm getting the same reply:

"as a brand registered seller you will have a higher rating over the contributions on the listings. Hence, seller support associates do not have an option to make the changes. Only Brand Registered seller will be able to make the changes from their selling account.

Please note that you previously entered the attribute value you now seek to change. When an ASIN is linked to your brand, Amazon increases the strength of your contributions and can prevent changes to specific attributes after their initial entry.

Examples of such attributes include, but are not limited to, the following:

catalogue_number

model_number

part_number

size

colour

Title

When you find that the locked product data on an ASIN is incorrect for any of these SKUs, the affected SKUs for the ASIN must be deleted for 24 hours, which will enable our system to allow changes to these locked attributes."

We have a lot of listings and quite frankly I'm struggling with the spreadsheets to add even the odd missing listing and the thought of having to take down and manually re-add everything is horrendous. Surely once we change the brand names, Amazon shouldn't be adding what is essentially another brand's name to our titles. Additionally, we did not enter the attribute to be changed in the title field.

I've found mixed answers on other people doing similar things so I hope maybe someone here can help.