Ed Sheeran has apologised to a London busker after she complained that she had been temporarily banned from Facebook for posting a video of herself singing one of his songs.

Charlotte Campbell criticised the singer in a video, saying “he isn’t Ed Sheeran … he’s just a brand”. But the star blamed his record label, insisting that he had not reported her to Facebook over the brief clip of her singing his song Castle on the Hill.

“Just seen your video, it definitely has nothing to do with me, I bloody love seeing people cover my songs,” he wrote in a post on the 27-year-old busker’s Facebook page. “One of the best things I get out of this job is seeing other people find enjoyment too.”

Sheeran added: “I asked what’s gone on and, apparently, it’s a bot that Warner have that works on some weird algorithm (I have no idea what that means) but it’s just bad luck that it was your video. I’ve had a word, and I’ll get it sorted. Sorry again. Keep doing what you do, tis ace.”

A bot is an application that carries out automated tasks online – often those that are repetitive and require little human supervision or interaction. Facebook gives artists and companies a tool to send in complaints if they believe their intellectual property rights are being infringed. The site only removes content if it receives a complaint.

Campbell, who busks on London’s South Bank, said she was locked out of her account for three days and warned her page would be permanently disabled if she continued to post material that violated Facebook’s terms.

“As a huge Ed Sheeran fan, I was pretty ecstatic to hear from Ed himself,” Campbell said on Monday. “I was shocked and a bit confused as to how he even heard about my ban. It was kind of a relief too, as the initial ban came out of nowhere and I was worried that my account would be disabled just as suddenly. Ed’s message was very comforting.

“I was upset when I made the video [criticising Sheeran] and I talked about how crushed I felt that major labels are cracking down on tiny artists like this. It can feel like big music companies want to keep small artists down when it’s already such a struggle to be heard.

“Ed Sheeran somehow saw that video, I think because the message resonated with a lot of people and it got shared quite a lot on social media.”

Warner Music Group did not respond to a request for comment. Facebook declined to comment.