Lack of customer service and response

I bought a pair for croc boots for my son on Superbalist on the 28th of April but due to lockdown I had to wait till the 9th of May for my order to arrive. I tried on the boots for my son and with a struggle he had it on, so excited we threw away the tags. Then when it came to taking it off it was a major struggle. He is a 20 month old tot and the size 6 won't come off easily and then trying to get it on his feet after was just a major struggle. I wanted to exchange the boots for a bigger size but, Superbalist os of the opinion that the warehouse won't accept it due to the tags being off, even-though the shoes was only tried on in the house and in a complete re-saleable condition. I mailed crocs and phoned on numerous occasions to ask if I can do an in-store exchange and absolutely no response. This is very unsettling having to R399 for shoes which can not be worn through no fault of our own.