I was employed by a UK based company that also has a DC office and worked freelance from there.
The bored was incorrectly informed that I was there full time.
But did you carry out any work of any kind while you were in the UK on your visits?
If you did, that is considered illegal working in the UK, whether you were there full time or just visiting.
Doing ANY form of work at all while in the UK as a visitor is illegal - whether it's paid or unpaid, whether you are employed in the UK or US, whether you do it in person or online.
There are some business activities that can be carried out as a visitor, but they are very specific (
https://www.gov.uk/standard-visitor-visa/overview):
If you visit the UK on business
You can apply for a Standard Visitor visa if you want to visit the UK for business-related activities, eg:
- you’re coming to the UK for a conference, meeting or training
- you want to take part in a specific sports-related event
- you’re an artist, entertainer or musician and coming to the UK to perform
- you’re an academic and are doing research or accompanying students on a study abroad programme
- you’re a doctor or dentist and are coming to the UK to take a clinical attachment or observer post
- you want to take the Professional and Linguistic Assessment Board (PLAB) test or sit the Objective Structured Clinical Examination (OSCE)
- you want to get funding to start, take over, join or run a business in the UK
To carry out any other business activity, you need to hold a visa that allows work (i.e Tier 2 Sponsored work visa).
Do you think I will be able to attend school in September?
Normally a simple refused entry to the UK shouldn't prevent you from getting a student visa, but it can mean the application will take longer to process as they have to look into the refused entry and the reasons for it.
What does your paperwork from the refusal say? If there is any mention of deception at all, the visa can be refused, but if not, you should hopefully be okay.
I would say that the best thing to so would be to apply for the Tier 4 student visa, include any paperwork from the refused entry and explain the situation in a cover letter.