My phone rings once when the Internet kicks out (or vice versa)

Erratically My landline phone rings once and at that time the Internet kicks out or the internet kicks out and the landline phone rings Once, I'm not sure which but both actions occur almost simultaneously The phone is still usable - so some of the other forum entries are different to this. It has occurred about 6 times today including twice in the middle of the night it hasn't done this for a long time but we had a few of these about 5 weeks ago. My BB is EE with a speedboat 1908 router EE also bill me for the landline and there is a speed light ADSL microfilter, the phone is in the hallway and the router in anotherroom Sometimes the phone will ring once when the Internet kicks back in (this happened twice in the middle of the night too) especially if I do not disconnect then reconnect the wi-fi Manually. I am using a Mac PC but have iPad,and Android Wi-fi connections too. When it goes off in the middle of the night it causes all sorts of problems. I have spoken to EE who say its unusual (!) and suggested I cleaned the Microfilter connections, which I have done Can't find this problem anywhere else - any suggestions?