I was employed for 11 months with this company. They have…

I was employed for 11 months with this company.
They have now terminated my employment.
The reason is that 7 months into my job I had an accident coaching junior football players out of work hours.
I had to have an operation to reconnect a muscle to my knee bone.
This has taken quite a few weeks to get right again and be fit for my maintenance work.
I had doctors certificates right through accept on the last certificate there was a gap of 14 days. The reason being when the specialist wrote out the off work certificate it turned out there was a 14 day gap to when I was able to get in to see the specialist for the next appointment. Not realising this myself at the time I asked the specialist on my last appointment date to back date the certificate to the previous two weeks so I would continue my certificate and time off work to give to my employer.
I saw my employer the same day as my doctors appointment but I had to return back to see him on the Monday after the weekend.
At this meeting I was told I didn't contact them and therefore lost my job because they considered I had a banded my job.
I had been into the employer about three time previous to this giving them my certificates and letting them know what was happening.
Previous to my freak accident I had always got on well with my employer and staff and did my work as asked and required with no complaints.
In fact they said to me they would have someone give me a hand when I returned .
I know I was a few weeks from work but I was not able to change that under the circumstances.
The employer has now over the last two or three weeks employed another person to do my job.

Do you think they are justified to do this to me as I kept in touch with them . They had never called me to see what was happening. They just straight up took the opportunity to cancel my employment with the two week gap between doctors certificates.That was remedied with my last appointment with the specialist.