I'm not a Tiscali user I'm an ADLS24 user, Tiscali themselves have proven themselves bad on the ISP raitings on DSLZone click here# rated 25th Place.
I'm pritty sure you can get a far better service if you moved to another isp.
What router do you have? Ile guide you on how you can get your full line stats.
Also what does samknows say you can get at your exchange? click here post back the results.