[exim] **** debug string too long - truncated **** error

I am no Sysadmin, just a frustrated victim of major backscattering,

I have a quite seriousproblem and so far my hosting provider could not
help me out.
I am on a shared server (linux, apache, config) running exim 4.68 in a
CPanel 11.18.2-RELEASE setting.

I was able to apply a regex filter to test incoming e-mail bodies (
myname.+@??? ) that would efficiently can the backscatter, but it
only works with short test messages .

In a real world environment, the pattern I need to recognize is not
always at the beginning of the message body and ,when it is closer to
the end the filtering does not work, I get the following error:

**** debug string too long - truncated ****


IMHO it appears to be a problem with the size of the message, maybe a
buffer issue, a file size limit? I am no Sysadmin and do not know what
to do.
So far, 3 different helpdesk experts of my hosting service could not
help. Any Idea?

Thank you