Evertrend refusing to replace a faulty product

I bought a 1082 EMS muscle stimulator as a gift for my husband. We received it around 14th January 2025, and gave it to him on the 2nd March. When he opened it he found the armbands not working. I went twice to the address on the website which is 50 Constantia Boulevard and both guards said there is no Evertrend on the premises. We raised a complaint on the 15th March 2025 but they refused to assist, saying 3 months warranty is over. Please intervene as I raised the family within the 3 months period