BT not connected broadband properly?

Not sure if the fault is with BT broadband service or the Open Reach engineer.

We had issues with Sky broadband not working and we saw a good deal at BT for super fast & decided to switch over from Sky to BT. We ordered an 18 month deal with BT for broadband (and line) and an Open Reach engineer came around and set it up.

He used the microfilter from our old sky box in the set up. He said there had been a fault in the line but it was sorted. Our new internet was up and running (yey!).

Now, today, just as my first bill is due (The direct debit shows up on my accounts direct debit list but no funds have been charged yet.) Our internet has been disconnected and on my BT account it says. 'No packages to show' and 'Your BT account is not connected to broadband.'

I don't understand what's happened. I spent an hour on the phone with BT trying to sort it and they ended the call with the proviso someone from Open Reach will be in touch. I have had no explanation of what the problem is as it seems the broadband box set up is fine, I just need my account connecting up to the 18 month contract, I thought BT could've done that or does that require Open Reach?

Has anyone else had this, does it sound like BT haven't set up our account properly, or the open reach fella didn't connect it properly? I don't understand how it worked for a few weeks without any issue if our account wasn't connected?

Thanks so much if anyone understands broadband better than I do, I'd greatly appreciate your opinion