I've been granted temporary admission to the UK for only three days. What can I do?

Are these real reasons under the immigration act?

This question absolutely boggles the mind. Are you saying an immigration officer just dreamed up something because, I dunno, they didn’t like your hair? Of course it is! The rule of law in the UK is reasonably strong (some consider the Magna Carta from 800 years ago establishing it). This is not a hut in the desert on the border between Inner and Outer Camelstan where the officer wants baksheesh to let you in and refuses you because you didn’t pay.

You appear to have committed the cardinal sin of over-answering immigration’s first questions. Canadians visit the UK for several weeks all the time – you presented them with a story of someone likely to stay longer than they should.

You probably got those extra questions based on your initial presentation. Appearances can matter; the immigration officer at the airport will make some quick judgements, primarily based on your answers to some initial questions about your trip, but your clothing, bags, physical appearance, and in some countries, racial profiling, can all be factors when you first arrive at the checkpoint. After those initial questions revealed concerns about your finances, it is not surprising that you were referred for additional questioning, the answers to which ultimately led to your refusal.

The UK will cheerfully admit people of limited means if they have a local sponsor – also helps if the sponsor is waiting outside. Yours wasn’t, which doesn’t speak well of him as a sponsor (or a boyfriend – if I didn’t pick up my GF at the airport she would go straight back home no matter what immigration said).

Since you now have multiple issues on file with UK Border, you have a problem. You can’t give them the story they want because it conflicts with what they already know. If you really want to spend a month there, marry the BF and apply for a spouse visa.

You failed your landing interview and got a Temporary Admission (TA) instead of “Leave to Enter”. You were served a removal notice which says at the bottom “IS.82 No AR RLE” (No appeal rights, Refusal of Leave to Enter”…

Are these real reasons under the immigration act?

They are absolutely real. They got you under Paragraph 320 of the rules, which itself is an extract of the Immigration Act 1971. Specifically Paragraph 320 sub paragraph 1

(1) the fact that entry is being sought for a purpose not covered by
these Rules;

…which is pointed out to you near the bottom of your notice (“…you have not sought…”). It means what they decided you were really visiting for would violate the rules. You have a funds parking issue, and they didn’t buy in to your story about having a bf. But you didn’t totally blow it because you got a TA.

Is there any way someone with temporary admission and who only came as
a visitor can fight against this?

Short of claiming asylum, there are no provisions in the rules to reverse this type of decision. An Immigration Officer has a mandate from the government to make this decision and to have the final word about it.

Is there a way I can apply for entry as a family vistor because we
have been together for sooo long?

This would be a specious, outside-the-rules visa application and has the risk of attracting a full-on ban (in addition to an automatic refusal).

Even the guards said that to me and that the reason was weak for
refusal.

They will say anything to contain the situation and keep things peaceful. Ignore this kind of chatter.

Can you do anything once this is granted is my question

No. The matter is closed and you need to get out before your TA expires. Don’t waste your whole weekend surfing the net in manic-panic mode because at the end, there’s nothing out there that can lead to extending your TA. Per the comment from Ismael Miguel (to whom thanks) don’t overstay. Note that if you try meddling with your TA, they can ‘up the ante’ and give you an ‘undesirable’ rating like what happened here: Refused Entry and Removed from the UK; What are the Consequences?

Lots of times people in your situation get removed from port straight-away, so you are lucky to be able to spend some time with your bf. You can enjoy the weekend. When you return to Canada, you should apply for entry clearance using one of the Canadian VFS offices (Canadian applications are sent to NYC for processing).

The immediate corollary to your question is:

Are they going to hold this against me when I apply for entry
clearance?

Yes, a little bit, but not as bad as an immediate removal from port, and certainly not the end of the world. Since they have issued you a removal notice, you should hang on to it and put the reference number down in the application…

When you get ready to apply for entry clearance you can check over the archives here for lots of useful information.