Answerphone problems after Talk Talk exchange mods

Fruitcake

We had a letter from Talk Talk saying new equipment had been installed in our local 'phone exchange and was going to be connected at the end of February. We were warned that we would be without 'phone and Internet for about an hour on the day specified. No problem afterwards, or so we thought. 'Phone and Internet worked fine, until someone left us a message on the answerphone later that day and there was a load high pitched noise for a few seconds after the message ended.
Over a period of about a week the noise gradually lasted longer and longer to a point where it was continuous, and then the answerphone stopped working completely. No problem with incoming and outgoing calls, or with the Internet.
Replaced the answerphone with an identical model so we didn't have to replace the additional handset. Got the same load high pitched noise for a few seconds after a message ended. Over the next few weeks the noise gradually got longer until it was continuous, then the answerphone packed up completely.
This problem started the same day that the (unspecified) new equipment was connected at the local exchange.
Talk Talk are investigating but so far have found nothing to explain the problem.
Anybody else experienced this.

Fruitcake

You Only Listen To Me When I'm Wrong

albertross_2

Are you using adsl filters on all the phones and a/m

Fruitcake

Yes, using ADSL filters on 'phone with answerphone, and non mains powered 'phone but was already using them before mods were done at the exchange.
I've tried the answerphone direct in the master 'phone socket but this made no difference. However this was after the problem first occurred.

Fruitcake

You Only Listen To Me When I'm Wrong