Absolute joke of a company.

Last week I ordered a parcel and received an email saying it would be delivered by DPD on Tuesday. I work Tuesdays, so used the DPD website to change my delivery date to Thursday (today); the one day I'm not working this week.
I received an email confirming my delivery change. That was all fine.

First thing Tuesday morning I then received another confirmation email telling me that I'd now changed my requested delivery date to Saturday. I didn't make this change and Saturday wasn't suitable to me as, again, I work Saturdays.
So I went to the website again and changed my delivery date to Thursday for the second time. Received another confirmation email. Sorted.

Today is Thursday and I've spent the morning of my one day off waiting for the confirmation of my one hour delivery slot that their emails promised me. Instead I've just received another email telling me that I've now changed my requested delivery date to Friday.
AGAIN I did not make this change. Why on Earth would I change the delivery date of a parcel that I'm sat in waiting for?

During this I have not once had any contact from DPD, except the automated confirmation emails, or had an explanation or an apology.
It seems like DPD feel they can decide when they actually need to deliver their customers parcels and if it's not suitable for THEM, they'll just change it, whether or not it's a date actually suitable for their customers.
Then, on top of that, they have the nerve to send me emails telling me that I'm the one that made this changes?

DPD obviously couldn't care less about their customers. I'll be using other delivery companies in the future.