Unjustified reminder of tire direct

Hello together, I have a problem with tires-direct, with which I have always been very satisfied with previous deliveries: In November 2010 I ordered 4 winter tyres via giga-reifen.de (which also belong to tires-directly). After a short time it turned out that a tire loses much air. So quickly complained, called, further procedure explained: tires-direct sends a spare tire to my tyre assembler, the tire to be reclaimed I have to pay for the delivered spare tires. I agreed by phone. Unfortunately, I had to go to the hospital for 4 weeks. After my return I got the current status by e-mail: 1. The spare tire was delivered. 2. I could not change it because I was flat. 3. The (new) spare tire was picked up directly after 3 weeks and probably wrongly 4. I immediately wrote by e-mail and fax after my return from the hospital that they should send a new tire, because I would still drive around with the defective one (only then sent the complaint form). 5. Nix heard more. Now yesterday an e-mail from Reifen-Direkt came, that the complaint was not justified because the manufacturer found no defect (clearly, that was also the new maturity). n). I should pay the delivered spare tires (76 €). I immediately wrote back that this is certainly a mistake and described the whole situation again. today’s reaction from Reifen-Direkt: 1. Remind about the invoice! I called the hotline, reached a rather bad German speaking employee and explained the whole thing to him again. He didn’t get that much, but wanted to take care of it. Somehow, however, I suspect that this is not possible. o will be successful… So again the whole matter will be sent by mail with all correspondence and fax logs by mail. So far no reaction. Now my question: What do I do if they continue to warn and drive up with heavy guns? They can’t charge you something that you didn’t get? Thank you for your help!!