It is pretty obvious you have been cloned
If you RTS every letter - a county court claim could slip thro
in which case you would have an undefended CCJ to contend with
[ and these are a pain ]
http://www.theanswerbank.co.uk/Law/Civil/Question1426700.html
has some quite good answers
BC of course scores highly
I dont ignore them but answer everyone
and you should write and keep copies
phoning is no good
and there is a specimen letter from BC in the answerbank ref I give
The relevant companies are meant to have tracing depts and also depts dealing with returned letters. The short answer is that they do s+d all about besides sit around on their batts drink coffee and send out a few more