When you coil Coax, you break the integrity of the shield if it's copper alone (no additional mylar shield) and knowing how the average Cable Co operates, they are almost certainly using the cheapest bulk cable they can find, which means probably copper braid only.
Most Coax cable, if you can find the spec, will have a minimum bend radius limitation. Again, the chances of you finding the spec for what your Cable Co uses is slim to none, but 6" is a pretty common number.
Also note that when you coil any cable you create an inductive element, and inductance can lead to instability in some cases. Coiling a power cable can trip breakers, for example, where if you instead lay the cable out in a straight line to take up the slack it may run your power tool all day.
In the end, it's best to cut it to the desired length and add a connector.
You don't have to do that yourself ... it's the installer's fault and it's the installer's problem to fix. Create a ticket. If they give you grief about the reason, hang up, and make something up and call again. The installer will fix it in five minutes when he gets to you.
On the other hand, maybe you do want to do it yourself ...