questionable online broker practices ?

Makes you wonder sometimes if some online brokers participate in share price manipulation
Here's a classic example
Just before the sweep the bid was at 2.8 for abt 380K and the seller at 3.3 for 2 K with next seller at 5 for 10K
Last sale price was 3.5 yesterday, none done today.
During the sweep the buyer pulls out leaving it 40K bid at 2.6 and seller drops his 2K to 3.0 ........ with last sale of course being 3.5
So I placed a small 35K bid at the last sp 3.5 over the seller at 3.0 for 2K to try entice few more out at 3.5 where a few were offered earlier. I am happy to accumulate all day at 3.5 given the work that's about to happen.
During the sweep the online broker cancelled me twice without notice !!!
Why is the online broker "allowing" the sp down with 2K shares ???
In fact he shouldn't be allowing a potential 16+ pct fall on 2 K shares espesh since I am a legitimate buyer at the last recorded sp
The company shld be made aware of such actions as shld any ombudsmen still around supposedly protecting ordinary shareholders.
I will put them to the test again in the morn's sweep and if same occurs I will be asking some serious questions.
Or maybe I shld keep my mouth shut and let them flush out larger lines for me on the cheap ???
Love to know who the seller at 3.0 is for 2K
THAT shld be a Q asked by the online broker themselves ....... if .........
Of course I could be mistaken with a vivid imagination under the influence of a Morgan Black on ice with a squeeze of lime haha.
Who really knows .............