Long-time lurker, first-time caller

We have 2 properties - one has fibre broadband with Spark, and one has a 4G wireless modem with Skinny. Both accounts show up and are paid off our Spark account.

I recently got the 2nd property connected up to fibre (it just arrived in the area), and would like to 'swap' my 4G Skinny connection swapped to fibre. I contacted Spark, and they basically said they couldn't help, and for me to contact Skinny. Skinny so far have been unable to help - note that as far as I know I don't have a Skinny account - just the Spark account. I could feasibly create a Skinny account and order the connection through them, but I'm concerned that 1. they won't have any knowledge of the already-connected Skinny 4g connection, and 2. It won't be on the combined Spark bill as it currently is.

Does this sound like a normal situation, and what's the easiest way on sorting it out? It's been going on 3 days trying to get help from Skinny via Facebook messenger.