Not sure what to suggest about your slow speed.
If it the same tower, so always at home or work you speed test.
Could be a well used tower so all sharing a bit of the bandwidth, We are not 250m from a tower in built up area so cant see it) and now getting this as turned phone into portable wifi point and linked computer to phone for internet access.
Is bad, goes upto 2meg something on a good day but mostly around 1mb down and 1or 2 hundred Kbs up so is poor just now.
Have you tried another tower with same set up, guessing portable so dongle for laptop or a smartphone.
Can you argue, no tower nearby so no good for your needs and try the not supplying good sppeds to be useless.
Upto 7.2 is the best, at work ( or was to 4 weeks ago) the tower there I would have used gave 3 or 4 meg, even 5 once or twice.
Does change but your seems bad if that al the time.
Just done again with different test server and this, more normal.
This site is good. See where tower is to home or work.
put in OX14 1PP
shelley close and closest tower for any provider is 3, why I picked and me thinks for upto 7.2Meg, not the best but useable, been in places like illfracmbe in Devon and most of the time, nothing and two Three network towers there but no network or 2G signal so no good and would not download anything worked and didnot, was blaiming the phone but back here not stopped once so them or dodgy area, what you are in I guess..
the delights of mobile. goes or does not, ok here in Oxfordshire driving around, illfracombe rubbish, guess you are in the illfracombe coverage (rubbish).
Would be moaning like you if had the 24 month contract and lived there.
The way it goes.
Try the mobile coverage on there site, goes it say good, if does and not ( and is not I guess), a argueing point.
Write to main uk complaints if not already done and register the letter so they cant use " never recieved sir".
Cant help but just my thoughts.