For most chord products, Chord themselves do not perform the battery replacement, it is performed by service centres, dealers or DIY (DIY the mojo battery is straightforward, because the battery cable is plug-in).
So the best that Chord can quote is the shipped price of the battery, then the service centre charges what it wants on top of that.
As an example of the variation of costs for the Mojo:
- Some dealers perform the battery replacement free of charge, so overall approx $50 for the battery
- Some service centres have been reported as asking $150 overall
- Some service centres have been reported as asking $350 overall
Chord are not being disrespectful to you, by not quoting a price. They do not know what the overall price would be, because it is so service centre dependent.
If as Chord state, very few TT batteries have been replaced, then there is very little historical data that they can use, to predict a price for you.