Hostile Environment

I took a legal assignment. The firm had a strange name and I had to answer the phones. I was not advised by the agency that I was to do the phones. I am a legal secretary. The main boss called in and commented on my accent and told me "If you answer the phone like that do not bother coming into work tomorrow." He then asked me what I was - I am English from the North of England. Yorkshire. I discussed it with the other attorney and I was told to leave and not come back. Secondly, I went on another assignment from the same agency - I was given first the time of 10:00 a.m. to start and then as I was leaving to go to the job the agency called me and told me 10:30 am. I got there at 10:15. The assignment was to run for 6 months and possibly go perm. At around 3:00 p.m. I got a call from the agency and the words were "pick up your things and leave immediately and call us." They would not tell me why. I had a panic attack as though something bad had happened to a family member. I called them from outside and was advised that it had put a bad taste in their mouth as I was LATE and the job was finished. I only did one task at the office that day. Then the agency told me that the desk would be too heavy for me. Please advise. I have discussed this last lot with the agency and they are skating around it all and not admitting fault. I felt like a common criminal. I am under doctors care for afib and clinical depression. I feel these incidents have worsened my condition.