Does she have a case if mom was given the wrong pill?

My mom is suffering with thyroid issues. At this point, it is attacking her heart. A month ago, the doctor prescribed her a med, with hopes that it would stop her heart from skipping and to bring the thyroid levels down. Yesterday, she was sent to the ER from her doctor because her heart was out of control. When we took it to another pharmacy, we were told that the pill she was prescribed was a water pill not a thyroid pill which caused her levels to skyrocket and lead to us going to the hospital for her heart. My mom asked the pharmacy about the pills and all of a sudden they said they were discontinued. They realized they gave her the wrong pill. But we investigated.