Download speed decreasing?

[Old Blue]

I've been with the Sky Max package now for just over one week.I have had continuing problems with very slow download speeds, which are decreasing on a daily basis.I've spend hours on the phone with technical support who after many hours now inform me that my line is only capable of 4MB download speed.I've tried everything they have suggested, and many other tips on this forum etc.Firstly i connected the router directly into the test socket hoping this may improve the situation(no luck there).I've used both the wireless option and the ethernet option, both seem exactly the same speed wise.According to my stats, i should be getting around 12MB download speed.Sky have now passed me over to tier three, but i've no idea if they can improve things.I'm thinking of cancelling the service, as i understand you have eight working days in which to cancel.Is it worth letting tier three try to help, or would i be better off getting out of this altogether?I've posted my stats, so hopefully someone here can advise me.Thanks in advance.
Stats are as follows-

/usr/sbin/adslctl: ADSL driver and PHY status
Status: Showtime Channel: INTR, Upstream rate = 704 Kbps, Downstream rate = 3424 Kbps
Link Power State: L0
Mode: G.DMT
Channel: Interleave
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 6.8 8.0
Attn(dB): 39.0 25.5
Pwr(dBm): 19.8 12.5
Max(Kbps): 3712 800
Rate (Kbps): 3424 704
G.dmt framing
K: 108(0) 23
R: 16 16
S: 2 8
D: 64 8
ADSL2 framing
MSGc: 1 1
B: 108 23
M: 2 8
T: 1 1
R: 16 16
S: 2.1467 8.6666
L: 872 192
D: 64 8
Counters
SF: 114210 114208
SFErr: 0 0
RS: 3883146 970768
RSCorr: 14 84
RSUnCorr: 0 0

HEC: 0 0
OCD: 0 0
LCD: 0 0
Total Cells: 15675656 0
Data Cells: 166813 0
Drop Cells: 0
Bit Errors: 0 0

ES: 0 0
SES: 0 0
UAS: 33 0
Total time = 33 min 10 sec
SF = 114210
CRC = 0
LOS = 0
LOF = 0
ES = 0
Latest 1 day time = 33 min 10 sec
SF = 114210
CRC = 0
LOS = 0
LOF = 0
ES = 0
Latest 15 minutes time = 3 min 10 sec
SF = 11233
CRC = 0
LOS = 0
LOF = 0
ES = 0
Previous 15 minutes time = 15 min 0 sec
SF = 52931
CRC = 0
LOS = 0
LOF = 0
ES = 0
Previous 1 day time = 0 sec
SF = 0
CRC = 0
LOS = 0
LOF = 0
ES = 0
15 minutes interval [-30 min to -15 min] time = 15 min 0 sec
SF = 50046
CRC = 0
LOS = 0
LOF = 0
ES = 0

[Saturday]

According to my stats, i should be getting around 12MB download speed.

Welcome to the forum

Not according to the stats you posted. Your router is connecting at 3424kbps so the maximum download speed you could get is ~2910kbps (3424x85%).

Why your router is connecting at 3424kbps is a different matter.

Potentially your attenuation at 39db would allow a connection speed of ~11500kbps on ADSL2+ and a little over 8000kbps on G.DMT.

You have not been capped. If you had been your noise margin would be much higher than 6.8db.

The problem is almost certainly a noisy line. If your router connects via the test socket at around 3424kbps then the noise is between you and the exchange.