HTB transfer failed!! Pop-up blocked

troubledOne

Aware of the deadline to transfer HTB ISA to Lifetime ISA in 17/18, I applied online early in Feb with my Lifetime ISA provider. The online application seemed to be submitted successfully. 3 weeks later, in March when I enquired of the status of the transfer, I was told that no application has been submitted! Apparently, application required two steps - online submission plus a physical form with wet signature! I am told my pop-up blocker may have stopped from appropriate message appearing, asking me to fill a physical form. By the time this was clarified, the deadline was past.
I have lost £600 in the process. Do I stand a chance to claim the loss? Do I go to Ombudsman?
I will really appreciate some guidance.