3 times i have took a faulty portable dvd back to argos?

3 times i have returned faulty dvd player back to argos,they gave me a replacment on each occasion,the last time they gave me a replacment they said thats it you cannot have any more if this one is faulty,guess what,its faulty it wont hold its charge.what i want to know is what are my rights,can i get another replacment and was she wrong to tell me i couldnt have any more