Help with migration! IMPORTANT! URGENTLY!

Please help!
I wrote twice here, I wrote to sales@backendless.com month ago. I can’t to get answer for my question. We pay money for your, but quality of support is awful.
I need to migration my app from 3.x version to 6.x. When use your instruction, had the error.

App ID 99FA5B16-7426-9BED-FFE9-5322C4CA9B00

New app for new version: ID 8392897F-5346-215F-FF0E-66F93B59B500

My application data (table schemes etc) are not uploaded. After clicking on the “Import” button, a window appears that the unzipping process is in progress and nothing else.

I have log from e-mail with error:java.lang.NullPointerException
1 12:37:29 IMPORT_DATA Importing Started.
2 12:37:29 IMPORT_DATA Preparing files to import
3 12:37:29 IMPORT_DATA Creating temporary tables
4 12:37:29 IMPORT_DATA Creating user’s tables
5 12:37:29 IMPORT_DATA Checking for existing views with the same names as in imported tables
6 12:37:29 IMPORT_DATA Checking denied, duplicate and dataSize for columns.
7 12:37:29 IMPORT_DATA Preparing Users table: initializing columns.
8 12:37:29 IMPORT_DATA Import of tables failed: null
9 12:37:29 IMPORT_DATA Importing failed. Exception:java.lang.NullPointerException
10
11 com.backendless.management.impex.manager.imports.data.CommonDatabaseUtils.ensureDataSize(CommonDatabaseUtils.java:71)
12 com.backendless.management.impex.manager.imports.data.ImportDataManager.initColumn(ImportDataManager.java:841)
13 com.backendless.management.impex.manager.imports.data.ImportDataManager.initColumns(ImportDataManager.java:812)
14 com.backendless.management.impex.manager.imports.data.ImportDataManager.initTables(ImportDataManager.java:759)
15 com.backendless.tasks.impex.ImportDataTask.doExecute(ImportDataTask.java:225)
16 com.backendless.tasks.impex.ImportDataTask.executeImpl(ImportDataTask.java:155)
17 com.backendless.tasks.impex.AbstractImportTask.execute(AbstractImportTask.java:71)
18 com.backendless.taskman.Task.run(Task.java:108)
19 com.backendless.taskman.TimeoutFixedThreadPoolExecutor.executeTaskWithTracker(TimeoutFixedThreadPoolExecutor.java:91)
20 com.backendless.taskman.TimeoutFixedThreadPoolExecutor.lambda$invoke$0(TimeoutFixedThreadPoolExecutor.java:39)
21 java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
22 java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
23 java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
24 java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
25 java.base/java.lang.Thread.run(Thread.java:829)

Please help!

Unfortunately, we do not support nether 3.x version itself nor migration to the 6.x from 3.x. There were about 2.5-3 years of free support for our customers to perform the migration.

According to your problem:
I’ve asked my colleagues to check the letter in the box sales.
They will definitely answer you either by letter or in this thread.

Hello!
Please, answer to me.
I had wrote to box sales 3 days. And I haven’t answer from you.
We have a short time for migration

I just responded to you via email.