perl -wle '

my $t = "ICAC=0&MFWD_NUM3=XXX&MFWD_NUM4=XXX&H_ABOPROFILID=3&RPCID=0&ACR_ON=0&MFWD_MODE=0&IN_APPLICAB=0&ACCESSNAME=SIP";

$t =~ s/&/\n/g;

print $t;

'
ICAC=0
MFWD_NUM3=XXX
MFWD_NUM4=XXX
H_ABOPROFILID=3
RPCID=0
ACR_ON=0
MFWD_MODE=0
IN_APPLICAB=0
ACCESSNAME=SIP