For landed properties, like your case you mentioned it was done by TM contractor, I assume it is NOT prelaid type, meaning initially your house does not have the fiber prelaid when the developer handed over to you, and when you subscribed for Unifi, then only TM contractor pulled in for you.
In this case, you can either choose to have the Time cable joined to your existing fiber (in a FTB) at your backdoor or front yard (depends where the cable coming from), this way minimize the recabling hassle inside your house.
The drawback of this is in the future if you decided to switch back to Maxis/Unifi, recabling has to be done again.
Another method is leave the existing cable as it is, then have Time SI to pull in their own cable, the drawback of this is there might be some hassle of cable pulling.

Thanks.