Open Reach caps speed until restart

[#1]

Hello, i been having issues after every 24 or so hours my open reach caps my speed to 10 download, and 10 Upload (getting average 9.87 DL/UPload)
Until i go and turn it off for 30 seconds and put it back on then i reach my speeds, 30+MB Download / 15+ Upload.

i used to have internet cut out's but since i brought my new router that's not an issue.

Can anyone help?

[#2]

Hi there,
Did you get the same speed issues on the previous router?
Are you still using the openreach modem or does the new router not need that?

[#3]

my router is This : TP link TL-WDR 3600
It requires a modem too, so open reach one supplied by plus net.
i believe it did yes, but the router you supplied kept disconnecting my internet this one does not.