Birkenstock Wrong Size Received – Ordered Size 42, Received Size 37

I ordered a pair of Birkenstock sandals in size 42 with order number 556777 on 30 August and received the package on 3 September in Ranchi. However, although I selected size 42 while ordering, the order started showing size 37 and I actually received size 37. Since realizing this, I have been trying to reach Birkenstock customer care for two days by calling 9717111774, but no one answers the phone and I have not been able to get any support. I request that you arrange a replacement for the same model in size 42. If size 42 is not available for this model, I kindly ask for a full refund of my payment and clear guidance on how and where to return the wrong-size product. I would like this issue to be resolved as soon as possible and to be contacted back about the process.